Munchkin Variations w/ Unique Rules

I'm hoping for a list of Munchkin variations that have different rules or mechanics. I've done some research online, but it's hard to find details on some of the less popular versions. I'll list what I know based on what I've played and read.

• Marvel Munchkin. Powers that are limited based on your character level. For example a level 2 character can use a rank 2 power, or 2 rank 1 powers. Marvel Munchkin also allows you to start off with a randomly chosen agent card that I believe would represent the race cards in normal fantasy Munchkin.

• Munchkin Apocalypse. I haven't played this, but I'm aware of the seal system which acts like a built-in game timer. Draw 7 seals, and the player with the highest combat bonus wins.

• Munchkin Cthulhu: I've read that this one has a timer built-in as well, like Apocalypse, but I'm not sure if it's the exact same mechanic or if there are any other unique features in this version.