Depending on quantity, I can again recommend fastenermarketplace.com
Shipping is prohibitive though unless you buy a lot.
I'm on my 3rd batch of 500, they just accidentally sent to my old address, so there was a delay.
Since it was Christmas, it took a couple of days to get a tracking # sorted out.
As far as I can tell, 1/16" and 1/8" increments are all you will find.
For specific sizes, you gotta have them made.