What about if we use materials as cosmetics?
I've got a few ideas in mind:
Shellshocker spikes as spikes (like the wretched armor)
Metal Chunks can be metal plates or rust
Monster Rocks could be used to outline armor
Monster leaf as vines
Monster bones for skulls
Mushrooms can be fungal growth
Squisher brains could be fleshy wounds
You should be able to customize it in a shop, you put the material in a slot and you can pay with coins or 2 emes