I just picked up a box of HSS small twist drills Microbox 0.5-2.2mm, guess what 0.7,0.9,1.1,1.4,1.6,1.7,1.9 and 2.1mm are missing grrrr.
If you're drilling a plastic enclosure then use HSS drill bit at low(ish) speed and drill a pilot hole first. Avoid carbide drills for this sort of job, they're exremely hard and very brittle, good for PCBs at high speed. If your carbide drill bit wanders or vibrates then say good bye drill bit.