Soaring Structures 2 is a neat mod that puts randomly generated islands above your world. They aren’t incredibly common but they are fun to find in your travels and provide an extra bit of adventure trying to reach them.
From a distance some may look like they don’t have much going on up there but they actually all have a lot packed into such a small space. Some simply have ruins with goodies to plunder on the surface.
But if you dig down you may come across a hidden dungeon with unknown treasures or despair!
Some islands are simpler but add a bit to the overall atmosphere like this floating island with frozen waterfalls.
Or this one found in the savanna, although you may still find chests and more buried beneath the surface!
Villages can also be found with villagers and animals going about their normal tasks only much higher off the ground.
And you may even find more ominous looking mini towers with several levels of enemy mobs guarding their own treasure!