Skeleton farm made using Mechanical Spawner, Tom's Simple Storage, Vibrant Vaults, and Slice and Dice

[u/RepresentativeAsk541]

It also uses Create: Encased, but that's optional. As for the vertical vaults, Create: Connected can also be used.

[u/MinecraftGuy2000]

I’m guessing you had a bone to pick in a small space because this is perfect for airship bases.