About :
Eidos is the requiered modpack to play on the eponymous server. It's not originally meant to be played in singleplayer, you may experience some performance issues.
World Gen :
Eidos is featuring an exclusive NeoForge version of TerraForged for 1.21.1 called NeoTerraForged.
It is paired with William Wythers' Overhauled Overworld and Eido-Flora to make the biomes more lifeful.
In addition, the caves are made way more detailed thanks to the Subterranean Wilderness Revival project.
Structures :
Several YUNG's mods and Integrated Dungeons and Structures addons make Eidos world way livelier.
You can also challenge the great trials of When Dungeons Arise with your friends !
If you're more the sedentary type, you can always settle and grow your own city with MineColonies and its addons.
Tech & Magic :
The modpack central aesthetic is a mix of magic (Ars Nouveau) and tech (Create).
Both of these mods are paired with addons such as Ars Technica and Create: Aeronautics.