The Deep Dark Mod is a 1.19 mod that adds a completely new dimension with new structures, items and blocks! The mod is currently still in development so not much has been added just yet

The mod is currently based on the 1.19 Deep Dark Expiremental Snapshot 1 which can be downloaded from the Official Minecraft Website. The mod also uses the 0.13.2 version of Fabric Loader and the 0.46.4+1.18 version of the Fabric API. For Fabric API to work you need to create a file named "fabric_loader_dependencies.json" in the config folder and in it write the following

{
  "version": 1,
  "overrides": {
    "fabric": {
      "depends": {
        "minecraft": "1.19-Deep.Dark.Experimental.Snapshot.1"
      }
    }
  }
}