A more difficult variant is snooker, played on a 12ft x 6ft table with tighter pockets and smaller balls.
It can be frustrating to play well, but when you "get it", it really is a beautiful game to play, and a real mental workout.
For anyone interested, Ronnie O'Sullivan is the best ever player, and his YouTube highlights are worth a watch: https://youtu.be/PE8XPHnCNpg - makes the game look incredibly easy, but I assure you, it's not!