You got any suggestions on things to add?
Those sets of stalactite - column - stalagmite* tiles are
gorgeous. But you seem, from the screenshot, to be intending those tiles for backgrounds only?
So, my suggestion:
Make scaled-up versions for foreground/on layer 3 use. Honestly, those shapes make me itch for custom-objects of their foreground versions...
You could also add in some accent tiles for the foreground, just a copy of a tile's regular version with an altered texture, or maybe a crystal growing from the side.
* Handy mnemonic: stalac
tites grow down from the
top, like a V, while stala
gmites grow from the
ground up, like a Λ.