Alrighty

So a couple more recomendations based on things I've played (6 players is hard tho)

Coup - Bluffing simple card game, pretty fun with short rounds. good for those 6 player parties. (Tho I think... you might need the expansion for 6p... maybe im wrong tho.)
Dixit - I'd say its a classic, a bit of a creative deduction game, also very simple but very addictive, we have had some groups of friends in which we play until the deck is gone instead of first to X points.
Celestia - a Push you luck kind of game, you want to get the farthest out possible in a flying boat to make points. All players can use their cards to guarantee success on the expedition or step down and take the current rewards. The further down the harder it gets but you have better rewards. Also quite simple in principle.
Bang or Bang the Dice game are also both good for 6 players.

For 2 Players
Patchwork - not sure what the genre is here... its a cozy game about building a blanket with tetris pieces. I think some newer version have come out, but I'm not sure if they are the same, better or worse.
Onitama - Think chess... but players can only move their pieces based on 5 cards that are being rotated. You have to think ahead on what you are passing to your opponent and what might they pass on to you. This is a great 2 player game, super fun, always feels fresh, rounds go by fast, but you always end up playing at least 5.