This is a little thumb protector I've made for our HEMA club, Gladiensis. You can sew some cloth/leather/sponge into it.

There are two little holes on the top to thread the needles in. I've used leather because why not. It should save from those nasty finger tip hits on the thumb. You can scale it to your finger. We just use it sideways in the club if the finger doesn't fit.

You can keep it in the glove for easy changes. 

You probably could use it for the other fingers, but might have to scale them.

Update: I've found that it is better to print it in TPU, so it is more easer to get in and out