No matter how much I remove them, sims constantly spawn gloves with their outerwear. Sure, I could just remove them, but it gets irritating to do it for the entire town.
Therefore, I'm looking for a mod for fingernails. Nothing flashy or long. Something really short, subtle, and available for children and older.

Hello AsaButler - I do not know where or if there are fingernails that can be applied over the gloves but if you have NRaas Retuner you might want to try this:

From City Hall or a Computer>NRaas>Retuner>Settings>General > By Tunable XML > Sims3.Gameplay.Actors > Sim
kChanceRandomGenOuterwearHasWinterGloves > set that to 0. You might need to exit and reload for it to work. It might take a sim day or so to kick in.

Another way to remove the gloves would be to install Kuree's EasyCASP Editor, select the Seasons EP (I think that's the only EP that has the gloves) and select to hide the gloves in CAS and unselect the use for random box. Also, if you have installed custom content gloves via 3Pack those can also be edited using EasyCASP. Custom Content CAS items installed via .package files can be edited using S3PE.

Also Buckley has a 'No gloves with outerwear' mod that works great, it has several options. You'll still have to manually remove the ones in the already assigned outfits, though.
No Gloves With Outerwear

Thank you for the advice.
Well, the No Gloves with Outerwear mod actually modifies the XML barbarat mentioned. Since that mod in incompatible with any that also alters curfew, I just went into the curfew mod I already have and changed it myself.