Micro applicators. Originally used in dental procedures for applying small amounts of adhesive or whatever, these things are about 3" long with a teeny-tiny bit of sponge at the tip. They're perfect for applying small amounts of CA or paint, especially in hard to reach places and work better than a toothpick. I picked up a case of 300 on eBay for 99 cents and am constantly surprised at the number of uses I'm finding for these little things.
Generic, no-name gray primer in a rattle can. I get mine at Pep Boys for about $2.50 on sale. Everything gets a coat. Sometimes, since I do a lot of Navy vehicles and railroad cars, that's the only paint they get, aside from weathering.
And, of course, my airbrush, which I've only had for about a year, but now I can't recall how I ever did anything without it.