Uno is definitely a classic!
I'm a big fan of Coup, there are several character cards which each give the player holding them certain actions they can perform. No one knows what cards each other have and you're allowed to lie and perform an action with a card not in your set. Other players can call your bluff and then you have to prove it. There's obviously a bit more to it but it's pretty easy to pick up and a lot of fun for various group sizes. Think the full name is Coup (The Dystopian Universe), definitely recommend!