I've always been a fan of anything relating to the World Wars. Loved working on this guy and if you'd like to purchase it you can find it here:
https://www.artstation.com/marketplace/p/XOp6B/ww2-german-helmet-game-and-cinematic-ready

This is a German helmet from WW2 that is game-ready with LODs and includes a high poly enough version for cinematics. Source files such as bake scenes and textures are included on the store.