The classics are good, Crazy 8's, Go Fish (which is better reversed, where you can see other people's hands but not your own), Egyptian Ratscrew, President/Scum, and so on, but I genuinely enjoy Mao the most.

Between the simple quality of the base rules and the fascinating depth, deduction, and memory puzzle as the game progresses... It's wonderful. Sadly, too many people choose to play the game as an inside joke or gatekeeping game, whereas the game is best played with a more teaching role at heart. Still penalize for failure to follow rules, but enunciate why and be deliberate about it, so they have a chance to learn from their mistakes, or others'!