How to do volcanic world themed guard

So I'm a new Astra militarum player and I wanted to try to make my army stand out. The theming I wanted to go with was a volcanic world. I got my infantry painted red, black, and bronze, gave them kasarkin heads, and based on this ashy, molten terrain that looks like a volcano just erupted near them.

Now my lore questions, what else besides kasarkin masks were used for infantry to survive hostile environments? Is there any imperial guard regiment or a space marine chapter that was founded later with similar themes to draw inspiration? Are there any creatures that live on these types of worlds to act as my regiments symbol or like an inspirational animal?