I've been using small endmills from Rogue Systems (maybe known as CNCToolGrinding, too). Ebay link:

https://www.ebay.com/str/carbidetoolsource

So far, I'm impressed by the tooling. Good range, uncoated carbide. Excellent prices, blindingly fast shipping, made in USA. Sell in 5 or 10 packs and up. 1/4" 3F high helix uncoated Al EM is around 9 bucks.