I'll be splitting this information between two posts. It's a heck of a lot of information, so utilize your Search Tool (Ctrl+F) to find things. This is a work in progress, it's 9 at night so I will be leaving this unfinished for now.
I will be referring to traits, skills etc by their ingame names. I will try to alphabetize this, though it's not in alphabetical order in the code, so I might get some traits out of order. I will try to remedy this.
Traits A-M:
Absent Minded:
Will pause to "think hard" at any time between 240 and 480 Sim Minutes - so if he thinks hard at midnight, he will not do it again until sometime between 4 and 8 AM.
They may "think hard" while cooking, there is a 10% chance of this.
Artistic:
If an Artistic Sim is learning painting, the skill gain rate is multiplied by 1.25. If they are learning Guitar, it is multiplied by 1.1. If they are learning Writing, it is also multiplied by 1.1.
Athletic:
If an Athletic Sim is learning Athletic, their skill gain rate is multiplied by 1.2. They will get fatigued at a slower rate - 0.8 times the normal rate.
Brave:
A brave Sim in the Military or Law Enforcement career gets a performance bonus of 3.
Charismatic:
If a Charismatic Sim is learning Charisma, the skill gain rate is multiplied by 1.25.
Coward:
Cowardly Sims will get scared of the dark between 9 PM and 5 AM.
Excitable:
An Excitable Sim routing towards another Sim in the Romantic or Friendly LTR State with a positive STC (someone please clarify the meaning of this!) has a chance of getting the Excited Buff - that chance is 25%.
Good Sense of Humor:
If a joke is good, the relationship benefit between the two Sims is multiplied by 1.5.
Green Thumb:
If a Sim with the Green Thumb trait is learning Gardening, the skill gain rate is multiplied by 1.25.
Evil:
An Evil Sim must be within 10 tiles of another Sim in a bad event to get the Fiendishly Delighted Buff. They also get a performance bonus of 3 when in the Criminal Career.
Genius:
Genius Sims will contemplate items within 3 tiles of themselves. The Contemplate interaction takes 8 minutes.