I think it would depend on the type of flies you tie. If you tye mostly drys the a couple of good necks, tailing material and dubbing. If s/h's then what ever material you may need there. It goes on for each style of fly. When I travel I take for good necks and tailing material. Partridge, starling and some hen necks. Thread you could get buy with black, white lt yellow and a olive. Hooks to match what you would tye. and two sets of dubbing. I like those little multi-compartment cubes. I have some seal, super fine, beaver and some nymph dubbing. CDC of various colors, elk and deer hair and some cheneil