10 suggestions for new traits.

Just a few ideas for traits that really help give a sim more character. I'm not fond of the ones that do little else but boost how fast some skills are learned. 

-Boring.  These sims are easy to please and content with pretty basic activities, their fun motive drains less fast than for other sims. They also won't do any interesting activities by themselves, meals they cook on their own are always the most bland options available. They can talk about mundane stuff with other sims, which will bore them unless they too are boring. These sims are content with a simple life and don't crave excitement, so the trait conflicts with such traits.

-Dumb. These sims are incapable of improving skills but can still get them through the wishing well or other rewards. They are also easily amused and can be particularly frustrating for genius sims in conversation, but their antics might also annoy some other sims. They might still try to use broken stuff and act surprised it doesn't work. They also are able to do some unique interactions like 'pull my finger' and stuff like that. They never feel embarrassed. They can laugh at themselves too and might even respond positively when targeted with mischief. 

-Jaded. Nothing phases these sims, they are unimpressed by whatever crazy thing happens. They just shrug and move on. Also means they won't panic or get scared, but won't do anything about it on their own either like put out a fire unless told to do it. It is more difficult for them to make friends with anyone who isn't also jaded, and learning skills could take a bit longer too because they aren't open minded. 

-Open minded. These sims are quicker to learn and make friends, quick to forgive too but do get hit by stronger negative buffs whenever they do feel betrayed by another sim. They might be a little naive at times, expecting the best of others. They could also be excited about trying new skills, getting the first few levels faster but later levels at the regular rate. They might dive enthusiastically in new things without worry, which can sometimes backfire on them. 

-Heavy sleeper. They can sleep anywhere without trouble, no amount of noise will wake them, it never causes them discomfort either even if they sleep on the floor. They could even go sleep in spots no other sim can. Like in the rocket which could have a chance to blast off into space whenever they sleep there, accidentally pushing the wrong button in their sleep.  They can also sleep on a slide, in a chair, on a yoga mat, in a bathtub, in a hottub and various other places, which might be annoying to other sims. Sleeping gives them fun too.

-Loud. These sims laugh loudly, snore loudly, make more noise when preparing a meal, sing louder too and just tend to cause a lot of noise. Also have some unique interactions like singing loudly at their mirror. When a loud sim screams, it wakes everyone on the lot too unless they are a heavy sleeper. They talk at a higher volume too, they don't do whispering. They themselves are not bothered by loud noises. 

-Quiet. These sims can be very sneaky, they are good at sneaking up on others and also not waking them or causing a ruckus. They get a few whisper interactions too, they enjoy quiet activities, and will often enough turn off radios and other devices that make noise. They don't get along well with loud sims, but could make excellent librarians. 

-Charlatan. These sims are real con artists, they will always look for short cuts. They can cheat in games, are likely to cheat in relationships, can tell tall tales and also various lies. They are also able to con other sims out of some money with all kinds of rigged hustles. They do however risk losing friends fast when caught in their web of lies and might also have to pay fines for failed hustles. They get unique interactions at jobs too to hustle in some way. They enjoy a good gamble too. 

-Mime. These sims don't talk, ever so can be used to simulate a mute or just someone who chooses not to speak. They do use hand gestures instead to communicate. They also have the option to mime, doing various mime motions to amuse other sims. 

-Lucky. A bit of a cheat trait, these sims always get the best possible results from anything with random chance. Always find the best items, win lotteries, nothing unfortunate ever happens to them by chance. It does however make them bad at actual hard work. They learn skills slower and are not so good with holding down a job. Things come easy for them so they take it for granted. They aren't good at comforting other sims because they can't relate to misfortune. When bad things do happen to them that have nothing to do with random chance so can't be avoided, they suffer stronger negative penalties for it though because they are terrible at coping with that.