There are a lot of stats out there. Some are fairly simple. Others are incredibly complex and there is no way to find the exact formula. I think there are 3 basic categories. The large majority of stats you will see are box score stats.
Box score stats- Some permutation of stats that are tracked in a box score. No matter how perfect your formula these stats have an inherent limit to usefulness since there are lots of important things that don't show up in box scores.
Player tracking- People rewatch games and evaluate players based on certain metrics. This sounds like a good idea but it seems fairly subjective even if you are an expert viewer.
Plus/Minus- Winning and losing is tracked in various lineups and/or statistical adjustments are made to the data. In theory this would be the best stat but in practice it is quite difficult to isolate one player's contribution from his teammates.
If there is a comprehensive list of publically available stats I'm not aware of it. If it doesn't exist it would be a good idea to make one. Here are a few sites that have some definitions-
http://stats.nba.com/help/glossaryhttp://www.basketball-reference.com/about/glossary.htmlhttp://www.nbastuffer.com/component/option,com_glossary/func,display/Itemid,90/catid,42/http://www.goldenstateofmind.com/2011/12/6/2602153/advanced-stats-primer