Precisebits (Tinker and Tinker) and on eBay, check out a seller “Drillman1”. Both have bits that are very small (less than 1/32)
Carbide 2-flute Wood and Plastic End-mills
https://rover.ebay.com/rover/0/0/0?mpre=https%3A%2F%2Fwww.ebay.com%2Fulk%2Fitm%2F152484463303
You can also use v-bits. I like the 30 degree ones for very thin cuts. Both these sellers also have these.
Warning: you need to clean out the collets very well, have very low runout, and a very rigid machine to be successful with these tiny bits.
Carbide 2-flute Wood and Plastic End-mills
https://rover.ebay.com/rover/0/0/0?mpre=https%3A%2F%2Fwww.ebay.com%2Fulk%2Fitm%2F152484463303
You can also use v-bits. I like the 30 degree ones for very thin cuts. Both these sellers also have these.
Warning: you need to clean out the collets very well, have very low runout, and a very rigid machine to be successful with these tiny bits.