What gods of mischief are there?

Norse mythology - Loki, started mischievous enough like cutting off Sif's hair, but then went from back to worse until he killed Balder and became the father of the monsters that lead the battle of Ragnarok.

Breaton mythology - Puk, "what fools these mortals be"

Greek mythology - Strife, started the Trojan War by challenging the goddesses to a beauty contest.