I have made 2 warhammer 40k skin for Nuclear Throne Togedher. A comissar one for Rebel (your allies are guardsmen), and an ork one for Steroids, both are fitting, awesome, and completly free. More is planned and i am open to suggestion as well.

https://dixout4h.itch.io/commissar-mod-for-ntt

https://dixout4h.itch.io/ork-skin-for-ntt