I know of Pandemic and I remember having played a game about mountain climbing where the goal was to as a team climb the mountain and get back down safely but there must be more of these games where one play as a team rather than against each other. Where can I find a good list of such 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.
Check out http://boardgamegeek.com/ and play with the advanced search feature. You'll find everything you need. It probably will be a better source of knowledge than your local game store, as BGG is not limited to what it has on the shelves and does not try to sell you something.
(btw, the game you played was most probably K2)
The link to boardgamegeek for coop games.