I started messing with the World Builder a few days ago. At first it was pretty rough, but pretty soon I had a good enough grasp and decided to start messing around with some ideas I had.
My vision for this biome was huge dome-like islands surrounded by colorful reefs. The worley noise I used as a base for the land gave me a few problems initially (it’s hard to put reefs in nigh-infinitely deep trenches) but once I cleared that issue up it began shape up quickly. In absence of coral blocks I decided to make the reefs out of leaves, so I guess that makes them “floral reefs.” 
Besides, plants like sunlight so it would make sense to find them in the shallows. If water creatures get added to the game I could see this biome being really exciting to explore!
I have yet to install caves in it but one thing I would like to try is to nearly hollow out the domes and punch a few holes through the shell to provide dramatic light shaft-lit caverns for builders, while still having the land atop the domes be viable for settlement.
I am not entirely sure what I will do for the other biomes, but one idea I have is to modify some Garbor noise to create a biome with sandbars and trenches
Comments, tips, and criticisms are welcome!