Feats are special features that either give a character a new capability, or improve one that they already have. Some use this term as an abbreviation for “general feat”, which is more correctly a subcategory of feats.
All feats from the base game are available on Sinfar, the original documentation can be found here: https://nwn.fandom.com/wiki/Category:Feats
Some of them have been slightly changed, see: PAGE INFO ALREADY TRANSFERRED TO THE NEW WIKI - Feats Changes.