My take on the origins mod, but as a plug-in for ease of use of use.

1. axolotl - Regeneration 1, and breathe underwater, and gain buffs underwater.
2. iron golem - You have 15 hearts, and powerful blows that send your opponents flying up.
3. enderman - You have 12 hearts, and if you shift right click with an empty hand, you teleport to the block that you're looking at.
4. blaze - You have fire resistance, slow falling, and if you right click with an empty hand, you shoot a small ball of fire
5. creeper - If you shift right click with an empty hand, you explode taking three hearts of damage and dealing damage to everyone around you.
6. shulker - Resistance 1, When you hit an enemy, there's a chance for you to give them levitation. When you get hit, there's a chance for you to teleport one block in any direction.
7. parrot - You have creative flight, slow falling, and when you right click with seeds in your hand, you consume them, and get Regeneration 2 for two seconds.
8. whither skeleton - You have fire resistance, strength, and when you hit an enemy, you give them whither.

This is work in progress, so expect bugs.