warm prairie
Idk if this is something planned already, but it would be cool if there were smaller biomes scattered through the larger ones that are relative to the larger biomes they inhabit.
Like an oasis in a desert, coral reef along a coast, or a giant mushroom forest inside a normal forest.
As for resources, perhaps they provide special resources used for an auxiliary system in the future as opposed to providing resources for the current "main" tier progression.