I have about 2 dozen different sets of drill bits - some for metal, some for wood, a few carbide tipped, cobalt, TiN, some for concrete, some cheap, some expensive all located in a cabinet under the drill press. I have two of the 115 piece sets of Letters, Numbers and Fractions, one in cobalt. I Zalsohave several sets of metric. The 115 piece sets do well as substitutes for normal pen sizes on occasion. And then there are my pen bits, kept separate. I have a rack I made some time ago in which I keep them.
Keeping bits and bushings together - that is too much organization for me. Kits - in the Dollar General $1 semi-clear shoe boxes.