Sets like this one
https://www.amazon.com/dp/B092D4CV56
are also sold in U.S. hardware stores
https://www.harborfreight.com/needle-file-set-10-piece-69876...
https://www.menards.com/main/tools/hand-tools/files/tool-sho...
They are very cheaply made, but as far as I can tell are actually diamond. They're good for shaping glass and ceramics. For metal, you're better off using hardened steel files, but these ones will work, just slowly and with less precision.