I couldn't find any cave walls that would fit the kind of theme I was looking for, so I made my own. A lot of these are based off of walls in the cave systems of Destiny 2's Io landscapes.
I may have gone out of control on the variations of these. So you can fill your game with walls that have dinosaur skeletons, a couple of different columns, etc. This also includes a cornerpiece and a door with stalagmites+tites (which will need to be printed with supports).
The mushrooms and crystals both have a hole set in the bottom in which you can insert an LED light. Use clear or white filament to print. Cover the sections you want to have glow, using blutak or similar, then spraypaint with your basecoat. The LED light should diffuse through the wall and make those items glow.