A modpack focused around the Aether.
This modpack is based around the mod known as the "Aether II" & "Aether Legacy". Here you'll have to find a way to survive and thrive.
The Overworld consists of only a spawn-island, on which you'll initially spawn, and on which there are two portals; one leading to the original Aether Dimension, and a second bringing you to the Necromancer Tower, which then brings you to the Aether II dimension.
Most of the ores that are known to generate in the overworld, such as iron, gold, diamonds, copper etc. now generate in the Aether, meaning you won't have to travel to the Overworld. This means you should be able to progress where you'd normally need iron and what-not. Regular dirt and the like can be acquired from composting biomatter in barrels.