Custom 3D Printing Miniature Design

Sorry if this is the wrong place, but it seemed the most appropriate. As a holiday gift to my players I like to get each of them a custom miniature of one of our tabletop rpgs. This year we have done a lot of Never Going Home, which I highly recommend, and as such I am trying to find a place to design models for them.

The game is in a World War I setting with Eldritch elements. I've used Heroforge for DnD models but they do not have any gasmasks or brodie helmets that fit the World War I vibe. I've tried Googling other custom 3d printing services and not been successful. Are there any recommended services? Or do people do custom commissions to make an stl. file?

Any input is greatly appreciated!