Where can I find a list of cooperative "beat the game" games?
BoardGameGeek's advanced search can be used to find a large list of co-op games. You can then sort or filter this list in several helpful ways. This form is a little bit daunting, but powerful. From the "Board Game Mechanic" list, select "Co-operative play". You will probably also want to check the "Filter Expansions" box and, if you are interested in widely available games, a minimum rating and minimum number of user ratings such as 200. (Here is a direct link which will perform that query for you.) You might want to sort the results by Geek Rating, which penalizes games that have fewer ratings, or by Average Rating, which does not.