Honestly I just use the Brooding, Loner and Shy and Socially Awkward traits for Autistic sims. It seems pretty legit for the aspergers side of things though you could add No Sense Of Humour if you wanted someone who hasn't overcome their literalism as they've grown up. Perfectionist also works for mimicing Autism as does Neurotic or Overemotional. Though they aren't as important as the first 4 traits I listed in imo.

Still it's kinda inconvinient to fill out ALL a sims trait slots with traits to simulate autism, so an autistic trait that incorported aspects of the traits I mentioned would be pretty useful.

There are few traits I have in mind...

Quiet: (This is not the same as shy!) Quiet sims don't mind being around people but they will never autonomously talk to other sims. Their social interactions won't do as well because they cannot hold a conversation for very long (Conflicts with loud, social butterfly, diva and charismatic)

Loud: Sims will ALWAYS talk, whether or not they are wanted to. If there are no other sims around they will sing, or make sounds to themselves because they have a dislike for silence. They will get a -5 moodlet if they are in a room with no talking sims, no turned on stereo, no turned on TV, no instruments being played, etc. unless they are sleeping. There's an upside and a downside though, because sims with the loud trait will be better social interactors as they are skilled at holding conversations for longer periods of time though the other sim in the conversation has a five percent chance of getting a bad moodlet called 'Not A word in' or something like that, and the description would be "It gets bothersome when someone goes on and on... Your sim can't even get a word into the conversation!" if the receiving end of the conversation isn't a social butterfly, friendly, charismatic, or loud aswell (Conflicts with quiet, loner, and shy)

Pushover: Pushover sims will do whatever anyone tells them to for fear of disappointing others and to get other sims to like them better. Possibly add some interactions like 'Offer to do homework' for teens, and 'Offer to babysit for free' for teens and adults towards adults with children. (Conflicts with assertive)

Assertive: Assertive sims will say it as it is, even if it ends up getting them in trouble. They won't be told what to do no matter who it is. For assertive sims there can be a chance that teens will get in trouble at school for arguing with the teacher and adult sims have a higher chance of getting fired, as well as a random chance of getting an instant promotion for speaking their mind. (Conflicts with pushover and bossy)

Bossy: Bossy sims love to tell other sims what to do. They like things done their way. They can order pushover sims to do their homework and chores (for teens), and do their laundry, go shopping for them, etc. If they are told off by any sim they get a -20 moodlet. They hold an extreme dislike for assertive sims and they love pushover sims (Conflicts with assertive)

Food Fanatic: They can eat and eat without getting stuffed. They get a bad moodlet from eating food that is less than very nice quality, and they get an extra moodlet for perfect and divine foods (divine foods being ambrosia)

Illiterate: Illiterate sims hate reading and writing and gain writing skill much slower. (Conflicts with Bookworm and Creative)

Creative: Creative sims excel in writing, painting, sculpting, inventing, and any other skill involving a creative process. The novels they write give a good moodlet to whomever reads them and the paintings and sculptures they create give a good moodlet to whoever views them. They will occasionally get a bad moodlet of 'Uninspired' that can last anywhere from a day to seven days that will have them unable to build any of their creative skills, the description for the moodlet being something like 'Creative Block is a dreadful thing for creative sims. Lack of inspiration can slow down the creative process drastically' And they can get rid of the moodlet sooner by 'Observing' which would be an interaction in which sims wander around town and simply observe in order to find inspiration, whether they're observing the ocean waves or a bar fight between citizens... (Conflicts with Can't stand art and Illiterate)

Apathetic: (I think this was mentioned but I'm adding it anyways) Apathetic sims have a lack of emotion and guilt. They simply don't get torn up over things like death and heartbreak. (AKA no bad moodlets for death or broken hearts) They aren't very patient with emotional sims and they can be insensitive at times. (Conflicts with over-emotional, hopeless romantic, hot-headed,nuturing, dramatic, and excitable)

I would also like an insomniac trait, though that's more self explanatory and doesn't need a description. (Not the same as light sleeper or night owl because they'll not be able to fall asleep/will wake up easily, but dread sleeping. Plus they'll more often resort to coffee to keep them wake instead of succumbing to sleep.

Plus, not every player has (or wants to) install every possible EP to get as many trait options as possible. Hence a sort of encompassing one, whether basegame or modded, would be helpful.

I want the Smooth trait, so that I can have Sims that are smooth as fuck. Like they'll just walk up to a girl and be like "hey" and 5 minutes later they're just fucking the shit out of each other.
And yeah, I want the Autistic trait. For the self-Sim.

The Collector/Messie: (Incompatible with Neat) Different from the Gatherer trait, this trait has Sims collect everything! Whatever they get their hands on - bugs; gems; furniture; whatever - they will keep collecting it, even when they don't need it. Unfortunately, they also tend to collect their bills and require some extra persuasion to get rid of them by actually paying. Their tendency to collect things or have it around them really irritates Neat Sims, who prefer to keep things tidy, if not minimalistic.

ugh, for the contrary I'd vote for "not beign a dog" trait (nothing against actual dogs, it's just an expression). Standard Sims' behaviour is terrible promiscuous even without any trait which could justify or just excuse that. I cannot leave one for a like 5min. without seeing later someone hitting on someone... Did some St. Augustin's worshippers actually made behaviour patterns in the game? "Free will is evil".

-.-

Sure, I'd like that too. But I want it to be easier for them to "cheat" on command. Like, I mean, you can't really have one night stands in this game. That's stupid.

I was gonna say, I can make them easily do it without them knowing each other well... then I realized I had Woohooer installed.

Be right back, installing Woohooer.

You know I'd really like Persona Traits for Plumbots, you know how in a lot of Sci-Fi you can customize the persona of your A.I.? It's be like that so you'd have like a Cat Girl persona for your Plumbot or a British Upper Class Persona and So on. I think it'd be cool if it also unlocked more design choices like the British Plumbot Trait gets you some butlery looking Plumbot parts whereas the Cat Girl trait gives your Plumbot an option for robot cat ears.

It'd be pretty useless overall, but in a sense I think Plumbots need more useless traits.

But for one that could be deceptively simple trait that would actually affect your game alot: how about Early Riser? No matter how tired they are this Sim will always wake up in the mornings even if they're in the red. On the one hand it's a very simple one trick trait for roleplaying...on the other hand good luck advancing your career if your the kind of Simmer who doesn't pay attention to your Sims bedtimes.

Insomniac: Sims with these trait have difficulty falling asleep or staying asleep. Unlike the Light Sleeper, who wakes up easily at sounds, the Insomniac could wake up at random points at night (or whenever they try to get some good sleep) and have trouble going back to sleep - it can easily lead to them getting frequented by the "Bad Night's Sleep" moodlet; but they tend to use the time between sleep by reading a book (including a skillbook, depending on what they have in their inventory).

Indecisive could be interesting, having a Sim make a decision (like accepting a career switch or learning a new skill) only to want to switch back after like a day. Imagine rolling the wish to learn the Guitar skill, paying for a class and buying a guitar...only for the Sim to want to sell it an hour later after someone boos them in the park, lol. Or overthinking things before making a decision - like walking around the ocean water a bit before going swimming, or sometimes spending too much time deciding on a movie/game/concert and missing a part of it (and getting the "Missed the Beginning" moodlet). Though I imagine it'd drive the SimGod insane

The associated LTW could be "Jack of all Trades", the one where you have to reach level 5 (?) of 4 different careers.

Clock-watcher: Give your sim a schedule and they will follow it autonomously to the best of their ability and get negative moodlets from being late.
And then whatever the opposite would be. Time-challenged? Time-oblivious? (I need that one for me. ) If they need to leave in 10 minutes, this will be the time they suddenly remember they forgot to shower, or have breakfast.

How about a Garrulous (talkative) trait. They just go on and on and on and... well, I needn't go on. They will corner perfect strangers and talk to them, whether they want be talked to or not, usually in places where it hard to escape. They will be utterly oblivious to the fact that nobody is in the least bit interested, and would just like it if went away. Their prime victims would be shy, mild mannered people who are just too polite to tell them to f**k off.

Hey, come to think of it, what about a 'Foul Mouthed' trait?

I think a trait that makes a sim seem more reserved than other sims would be pretty good. Really the only trait that really does that in game is Brooding, but traits that dulled the emotional output of a Sims animations would be cool. It'd be cool if they also had a more monotonous voice during conversations.

I've always hated how Sims all seem to react to things with the same degree of emotion. I kind of wish there was more of a variey in the way that sims reacted to certain events. Some traits help alittle bit, like the Brooding specific mourn and the Brave, Supernatural Fan, and Daredevil reactions to ghosts but I feel it's an under utilized concept.

So an Emotionless, or Stoical trait would be pretty useful in my opinion. As would a Mute trait that replaced normal conversation animations with an open mouth with something less verbal.

Loves Music: get a higher Moodlet when listening to the right music, likes to learn instruments and dancing, so those actions are done more often automatically. if they have a choice between different sport methods, they will choose the ballet bar over gym equipment or basketball.

Curious in the world: Higher interest in Science, some of the Nerd interactions unlocked perhaps.

You can see I am missing Freetime from Sims 2^^

Yeah; I hated how your personality points determined what your favorite hobby was and the wishes being clogged up with "x about hobby" all the time, but it was certainly fun.

Highmmunity: Sims with this trait have a naturally stronger immune system and are less likely to get sick when drenched or tired; allergies are also less likely to appear after sniffing (some) flowers. Because of their strong immune system and stomach, they can even eat spoiled food, without fear of being sick.

"Simmer". Isn't obvious?
There could be very useful interactions "Argue about Sim game version superiority", "Rant about ...", "Play your legacy", "Research a new Custom Content", "Mod your game", "Build a new house" and so on...
And moodlets - "Getting stuck", "One more day syndrome"... hm?

I was kind of thinking of adding two traits to this list:
Murderer
They will have wishes to murder people and the ability to bury bodies. They will have a new interaction: murder.

Yandere
This is kind of a mix of multiple trait things into one trait:
Clingy, manipulator, quiet, apathetic, maybe stoic, and obviously the murderer trait.
They will kind of "choose" someone they want to marry in the child stage and that will be their life time wish. They will have wishes to murder people who get too close to their senpai or develop even the slightest love meter. But, these are the only wishes they will ever get, except maybe "see the ghost of"
Obliviously, they can actually go to a jail and will get a "caught! now senpai will never love me!" moodlet with maybe a harsh penalty, like -50 for the rest of their life. From then on the person they "chose" will never talk to them again and always turn away their gestures.
Maybe they should be allowed no romantic gestures at all unless it is towards their senpai.
they will have interactions like "dream about senpai" "draw picture of senpai" "plan wedding to senpai" "research children names" "psych self up to talk to senpai" "plot next murder" and some other ones too!
these two traits would be perfect for a murderer challenge.

Carnivore: Incompatible with Vegetarian - Sims with this trait love their meat! Chicken, beef, lamb, pork - if it once walked around, they'll delight in eating it. They get a special little moodlet for ingesting meat recipes and turn their nose up at any sort of 'rabbit food'. If they do happen to eat non-meat recipes, they get less Hunger filled from it and will get hungry again quickly, because they don't feel satiated.

Two conflicting traits: Curious and Likes Privacy

Curious sims are eager to know everything about everyone and about the world in general. They get stronger positive moodlets from gossiping, and even have the "Ask about latest rumors" interaction under Friendly. Other interactions are "Peep into the window" and "Listen at the door". You can do it by clicking on a window of the neighbors' house any time, or the window of a room in their own house, where other members of the household are making out, kissing, woohooing, or even just gossiping). Positive moodlets from seeing something like neighbors fighting, parents scolding their kids, party at the neighbors house, someone aging up, sims making out/kissing/woohooing, a pregnant sim in labor, a werewolf shifting, etc. Negative "There's nothing interesting going on" moodlet from seeing just an empty room or sims doing boring casual stuff, like cooking, reading, casual chatting, sleeping, etc. Anything "interesting" seen in the neighbor's house can be later gossiped about. Sims with traits like Social Butterfly, Friendly, Charismatic are eager to share the "news" with others. Charismatic sims would benefit the most from sharing rumors, unless they are interacting with a sim who Likes Privacy, or the sim whom they were secretly watching. There is a risk of being caught by the neighbors (or household members who were seen woohooing) with a relationship meter decrease. Relationships with sims with Likes Privacy trait suffer the most, and are difficult to repair after peeping/listening.
Curious children like to watch other people showering, using the toilet, or skinnydipping. If they are also lucky and/or Rebels, they have less risk of being caught and scolded.
Curious sims of any age are also likely to dissemble appliances to see what's inside. The interaction is similar to the one available after a sim gets at least 1 score in Handiness. However, if a curious sim dissembles something without any Handiness skill, he/she just breaks the appliance, and it needs to be repaired by either a service sim or any sim who has Handiness skill. Curious sims can also dig into the neighbors' trashcans, or, if they are Compute Whizes, hack their dating site profiles or blogs (and send messages from there and post from there, yes).
Another interesting interaction is Explore the Abandoned Warehouse. This is done in a Criminal rabbithole, which is thought to be an abandoned warehouse by most of the townsfolk. The results can be: 1) Nothing Interesting found (slight negative moodlet because of disappointment); 2) Witnessed a crime (strong positive moodlet; the sim can report the crime to the police, and/or talk about it to other sims); 3) Beaten and kicked out (the sim appears from the RH entrance, holding to their hurting body parts, and even needs to go to hospital for wound treatment). Brave and Lucky sims have higher chances of witnessing a crime; Cowards and Unlucky sims have higher chances to be beaten and kicked out.
Curious sims can be Loners and Shy. Loners don't like to be among strangers, but, if they are Curious, they do like watching them. Shy sims would receive stronger negative moodlets from being caught peeping or listening at the door, and don't ask anyone about the rumors unless they are Friends or above with another sim.
This trait is beneficial for Investigator and Journalist careers.
Curious sims are also likely to often generate wishes like Visit Graveyard, Vault of Antiquity, Supernatural Hangout (esp. if they are Supernatural Fans).
While wishes are common for all Curious sims, the outcomes and reaction depend heavily on other traits this sim has.

Now, about sims who Like Privacy:
Such sims want to have their yard fenced and their windows dressed; they get negative moodlets from bare windows and open yard. If all the windows are dressed, and the yard is enclosed, they have a strong positive "My home is my castle' moodlet. Privacy-loving sims can be Flirty, but they don't like to perform romantic interaction in public, and would most likely reject anything except for "Compliment Appearance" , "Compliment Personality" and "Give a Compliment". If the relationship is very high, they, however, would accept other interactions (maybe even woohoo), but this will result in a negative moodlet.
Such sims are especially conscious about romantic interactions with supernaturals (because it is considered "scandalous' in the sim-world), or with anyone if they or their romantic interest has multiple partners.
They shoo even their spouses out of the bathroom. Also, they don't want to be seen in their sleepwear by anyone except for their family members, or other households members with whom they are friends. Living in a dorm or an apartment would give them a negative "too small private space" moodlet.
Sims who Like Privacy can be at the same time Loners or Shy, which makes them the hardest target to befriend or romance, but they also can be Friendly, or Party Animals, or Social Butterflies. Those more outgoing types are actually happy to have more friends and to have fun together with other sims; however, they react negatively to questions about career, school, star sign, partner. To ask any of these questions, you must be at least friends with privacy-loving sim. However, they would gladly discuss weather, hobbies, interests (and prefer to hang out with sims whose traits, skills, and skill levels are very similar to their own). Also, they like to dance and play games together, throw parties and accept invitations to parties.
Privacy-loving sims can become celebrities by socializing with other celebrities, just like any other sims. However, they don't enjoy their status! They receive negative moodlets from paparazzi, and can even attack them to break the camera (esp. Evil, Hot-Headed, and Mean-Spirited sims).
This trait is beneficial for Criminal Career (less chance to be caught by police), and Investigator Career (less chance to be caught by criminals).

Lethal Cook - these Sims can't cook. They may enjoy food and cooking, but they tend to mess up some way. They tend to burn food more likely and have more difficulty raising their cooking skill; they also leave messes in the kitchen.

Wouldn't that be hoarding rather than collecting? I would love to have something for my art collector sim but I have to make do with snob for him.