Four major terrains per region:
MIDLANDS
These are the warm and abundant lands that new players spawn in.
Crops: Carrot, Flax, Grapes, Hemp, Onion, Poppy, Pumpkin, Tea, Wheat
Wildlife: Ants, Auroch, Boar, Cock, Dragonfly, Fox, Hare, Hen, Ladybug, Moth, Rat, Toad
Storms: Rain (good)
- █ rocky: Mudflat
██ grass: Grass/Heath
██ swamp: Swamp/Fen
█ forest: Broadleaf
Cold and harsh wilderness wherein many dangerous creatures might be found.
Crops: Carrot, Onion, Hemp, Tea, Wheat
Wildlife: Bear, Deer, Eagle, Hare, Mouflon, Rat, Toad, Wolf
Storms: Snow (bad)
- █ rocky: Mountain
█ grass: Moor
█ swamp: Bog
█ forest: Taiga
MISCELLANEOUS
- █ deeps
█ shallows
█ shore
This only uses existing content for now, to make things easier to implement. If devs add terrain you could work a third region into this, lowlands maybe, but any more than that would be muddying the system.
Regions would solve the early game problem of spawning characters in terrain where they can't really progress that well, like coniferous forest.