Kit Spleef is a fun minigame where you have a range of awesome effects weapon to choose and stuff to do.
Among the weapons are Bows which with every shoot will blow up and dig a hole – I imagine this is more like an RPG.
A Sword that when you hit around will dig a hole – It can kill and works like a shovel.
Client Version: 1.8 , 1.9
Other than that you can capture mob and respawn them like a Pokemon game or you could kill other players by spawning speedy creepers.
This type of game usually made for playing with friends but Kit Spleef has option to play with CPU. Isn’t that great forever alone?