Amazon has a #61-#80 set of drill bits for the low price of $3.95.
These bits are definitely not high quality, but it’s worth keeping a set around just in case you have to drill a tiny hole from time to time. Bits this small are also handy for cleaning out small orifices by hand or even gauging holes if you don’t have a set of wire gauges that small. The description is confusing as it labels the size in mm, but we’re reasonably sure they’re number gauge bits. The case is definitely a throwaway, though, compared to the small metal indexes sets usually come in.