The Best

This list includes games where all players work together to defeat the game.  There are some games on this list that include "Traitor" mechanics where a player may be working against you (like Shadows Over Camelot or Dead of Winter), but they are not a guaranteed component in the game (like in Battlestar Galactica and Room 25).  

Not included on this list are also the partially cooperative games where 1 player plays the bad guys against everyone else (like Fury of Dracula and Last Night on Earth).  Those games are listed here: http://www.ranker.com/list/best-and-_34_semi-and-_34_-cooperative-table-top-games/ianmichaelenriquez