I used a 2" deep by 8" long by six " wide firm, thick cardboard box, from a computer hard drive, as a tool caddy. I used an exacto knife where needed to cut shaped holes for specific items - flexament holder, cement and thinner holder, stacker, etc. the rest I just pushed or punched a hole with the implement (carefully) to get the right size. (I also use the knife, crafts not carpet cutting, for cutting threads)
I hang a small plastic bag by the handle off the adjuster knob of my vice - the handle part is long enough, and the bag small and light enough it doesn't get in my way.
I use a loop of EXTREMELY fine copper wire as a bobbin threader - is stiff enough to be inserted without encouragement
I use plastic jar lids to hold beads or water for soaking biots and quills
I have used plastic twist ties to hold materials out of the way on a fly during tying
I have three or four different thickness needles stuck in a piece of foam. Each one as a different colored ball of head cement/nail polish on it to designate usage - head of cement, head of flexament or spreader, pick. Also makes them easier to hold. I also stick the flies around the edges to dry - ones that are small enough. I have two bodkins, but I find the tips too thick for smaller flies