I'm not sure if I'm posting this in the right area, so sorry if this is in the wrong spot.

I tend to stick to MTS and TSR for my CC. But I've been wanting to branch out and download from creators like NYGirl, Simpliciaty, and MyStuff. Creators that use Adfly, which I don't really trust. I lost my main computer to Ransomware a year or so back and have been hyper paranoid about pretty much everything online, but there's some great CC out there that I'd like to use. I recently added an Adfly skipper to bypass Adfly and it's sketchy ads, but I guess I wanted to hear other's experiences with Adfly CC and private creators? Yay or Nay?

In short, I have downloaded 30GB something CC, lots of them from creators who use adfly that you listed, NYGirl, simpliciaty, blahberrypancake, marigold, coupurelectrique ... I can confirm the CC itself is SAFE.
The creators who uploaded them are generous and kind-hearted humans, they dont upload virus to destroy the Internet and your PC. On the other hand, you are right to suspect that ad-fly practice is shady, because it integrates ads into annoying popups which act like boobies trap to distract you so if you are highly concerned, you should learn to protect your computer from those nuisances first. Use PopUp Blocker, AdBlock Plus extensions, and AdFly skipper: this combo is thoroughly tested on my Chrome browser, its lethal, it kills every popup and gives you the package you wish for in 1 second. If you are not using them (to support the creator with ad revenue) then follow this instruction: WAIT 5 seconds and click SKIP AD, you should use hotkey ALT+F4 to close popup if any (trying to click the Close X button usually just generate more of them), dont click on ads and flashy DOWNLOAD button, dont just blindly click to install EXE files (so many fell for this then blame the cc creators for infection, I really dont understand that logic, oh and I cant wait for the pro-EA crowd to declare any cc creator who dare to use AdFly and Patreon as bloodtraitor as if EA would be so charitable to release free content everyday like every other cc maker). Many gullible internet users contract malwares, spywares when they recklessly click away, so look at where you are clicking first.
I dont have fancy antivirus, just default Window Defender and I have waited many 5 seconds, its a bit annoying but I think of people spending hours to make this piece of toy I am gonna play with and I am happy to support them with my 5 seconds, my computer is fine with that too.
But you dont have to tread into this murky water if you are so afraid and unprepared, just back off to your safe space and tell yourself you can live without all these shiny sparkling stuffs on your dollies pixels, thats okay too

Actually, there have been a few threads discussing ad.fly which might be helpful

http://www.modthesims.info/showthre...highlight=adfly
http://www.modthesims.info/showthre...highlight=adfly

From my personal experience though, I had to download a ton of plugins just to avoid weird ads to show up that would take forever to close since it would show pop ups like 'oh no your computer has been hacked!' which... is of course not true, but it's really hard to get rid off when you're having those kinds of popups. Or ads that just makes you download viruses that you're not even aware of downloading. Of course that's not the case for all ad.fly links, but they do pop up a lot whenever you're CC hoarding

I’ve downloaded a lot of cc over the years for all of my Sims games and a lot of them use ad.fly. I’ve never had any problems, but I ensure my anti-virus is up to date just in case. I only use my Windows laptop for the Sims and try to keep it as clean from viruses as I can.

I have yet to get a virus from any CC involving adf.ly or similar sites. Just pop-ups. Oh and pop-unders, too.

The CC is never really the problem. Unfortunately, my adblocker freaks the hell out when I try to click the link. I love supporting artists but the ads overwhelm my computer

No, it's not safe.
You've already lost a computer so you should know that you have to keep your protection up to date and active. If you've done so I think you're fine to download.

If you're downloading from Patreon (Like Simpliciaty) then you should be fine.