League Of Legends has a variety of different champions that are separated into categories of: Tanks, Fighters, Slayers, Mages, Controllers, and Marksmen.

Here are some champions for each class:
Tanks: Sion, Shen, Cho'Gath
Fighters: Jax, Darius, Renekton
Slayers: Talon, Zed, Kassadin
Mages: Veigar, Viktor, Ahri
Controllers: Thresh, Blitzcrank, Pyke
Marksmen: Draven, Vayne, Twitch
It is also important to note that each champion has four abilities, and one passive.