Mulligans
General Mulligans
A stanard mulligan is looking for 1-2 of your 2 drops or a 1 drop to get your early board going and maybe a 3 drop if you can.
Aggro Mulligans
Versus aggro decks, you are more than likely going to be racing for damage to the face. Haunted Creeper and Knife Juggler will trade well with early minions like Abusive Sergeant and Leper Gnome, and try to set up a large taunt with Houndmaster.
Midrange Mulligans
Standard Mulligan
Combo Mulligans
Standard Mulligan but especially with Oil Rogue the correct timing of Loatheb can win the game.