The flying island is an upgrade to the old style skyblock world where you have much more room to venture and build, more resources and more challenges due to the limited number of blocks in this world, the number of mobs is even higher in the caves!
In this project, you can find an elaborate cave structure similar to the vanilla cave system with many mobs to fight through for resources. There is also:
Oak Forest
Birch Forest
Ore distribution is similar to vanilla Minecraft, can you get to the diamonds?!
Hills
Waterfall
100 x 100 blocks island roughly 150 blocks in height
Here is my tutorial on how to create a flying island!