DNA. I would like to mix DNA of new mobs, and a new utility block that mixes a crafting table and a furnace. This utility block would let you mix DNA of up to 3 different mobs, mutts, and/or dog breeds. This would be game changing, please add this in.
New dog breeds: Chihuahuas, Beagles, Pugs, Golden and Labrador Retrievers, and mutts of those dog breeds and Super Mutts of two mutts you create (a super mutt is the mixed version of two or more mutts and a mutt is a mixed version of two dog breeds)
Fossils/End fossils Since there are fossils in the Nether and Overworld, I think there should be fossils in the End too. And the fossils that exist aren't that cool except being rare. I think you should add a better and cooler use for fossils. There could be more mobs that you could use that utility block that I stated before to mix the DNA of those fossils. Then, after about 5 minutes (real life time) you would be able to summon a new mob of the DNA that you mixed.
TIMING FOR THE UTILITY BLOCK: About 2 to 5 minutes real life time.