Just got the hostile mobs and turned them into spawners so you wouldn't have to. All the hostile mobs have been changed to spawners, so all you have to do is go onto MCedit and import them.

YOU NEED TO USE "MCEDIT" IF YOU WANT TO ADD THIS INTO A MINECRAFT WORLD

These mobs ARE edited a bit, using SethBling's filter "Add Potion Effects" I added a potion effect so the mobs will spawn with that effect, Regeneration 2, Resistance 1, and Strength 1.

If you would like a certain mob with certain effects, armour, weapons, etc, just message me an I will be more than happy to make you one.

If you're wondering how this is made, all I did was go into Minecraft, spawn the mobs, then go into Mcedit to add the potion effects to the mobs FIRST (Used SethBling's "Add Potion Effects" filter), then change them into spawners (Used SethBling's "Create Spawners" filter).

Mobs: Zombie, Skeleton, Blaze, Cave Spider, Spider, Creeper, Lightning Creeper, Enderman, Ghast, Pig Zombie, Silverfish, Witch, Zombie

TO DOWNLOAD, CLICK "MINECRAFT WORLD SAVE", IT'S A LINK TO DOWNLOAD THE ZIP FILE THAT CONTAINS ALL THE SCHEMATICS.
I could only add one schematic at a time, and I couldn't put the folder of the entire thing under "Media Add"

*Feel free to use this in anyway you'd like, edit it, use it in maps, just for fun, no permission or credits required