The Spooky Lowlands Barrows biome needs to have barrows and barrow wights (such as those in the lord of the rings). Perhaps you can sometimes find treasure in said barrows.

Also, barrows should have wight mob spawners occasionally, and a mini boss version of the wight should exist (Wight Lord?)

Still waiting on wights themselves to be made so this can be resolved

Also should have a mini boss called the “Wight Lord” or “Wight King”

Barrows, which have now been added, should generate loot chests and wight spawners in the hollow areas.