Jesus, Why didn't anyone ask when I worked at the piano company ?
We had miles of the stuff, all colours and thickness's. If we didn't have the right thickness we had the skiving machines to par it to any size.
I used to get white felt cut 3/8" x 3/8" in foot strips for the vintage car boys for rear oil seals on the cranks.
Might still have a bit of this left, I'll check later.
I think I put 1/8" green felt in the bottom of my wooden toolboxes but this will be quite grubby by now.