If you want scenery for your cave dwelling Greenskins though, I have to point you in the direction of Grabblecast. Grabblecast focus on scenery and have two categories that fit our scheme here: Mushrooms and Dark Caves. The first category contains some forms of living and more literal living mushrooms and Dark Caves contains some stalagmites:
The Myconoids are $22, the mushrooms shown are $32 and the set of cave scenery is $17. Most of these are available in smaller packs as well. If you want to fit out your cave you can buy the terrain on Grabblecasts website and follow them on Facebook. All pictures shown above belong to Grabblecast.