I found the Avengers font online - put it into Paint 3D, added the name of a friends' kid, and then put it into a circle (coin or coaster) style shape. I am planning on printing this shortly, and will upload pictures. Any name or words can be used with the font - and there are a variety of free and paid fonts out there. I can provide other names too by request.
Up to you
I went with a PLA silver for my first print - but really it doesn't matter and you can print in any color or style, doesn't require and supports or raft, provided you don't print it too big and your heat is correct for your material.
I may color the inside using a marker, but it is up to you.