Star/Sky Dimension

Image if there was a city above the clouds with creatures you couldn't even dream of. I think that it would be awesome if there was another dimension where you had to use different materials like diamonds and gold and a nether star to make a block called a star portal block. Then once you have that block you can make a Star portal that teleports you to the star dimension where there are angels who protect the lands that only attack if threatened. There are flying livestock, and if you're luck you can come across a Pegasus  which you can ride and tame. There would also be a boss like a Star dragon and when you defeat it you can get an egg that you can hatch and tame.