Trying to source a BB86 BB the other day and seeing a thread on BB30 a couple of minutes set my mind wandering... I'm a bike mechanic and I don't even have a clue!
I'm thinking stuff that you can still buy, not something from 1930...
A quick thought to start proceedings and to delay cooking breakfast a bit longer:
Square taper - JIS plus all the axle lengths
Square taper - ISO plus all the axle lengths
For above you've got 68, 73 or 70mm (Ita) to cover most BB options.
ISIS - 68 / 73 / 83mm / 100mm BBs but all the different axles.
External BB - 24mm axle. 68 / 73 / 83mm.
Exernal BB - 19mm axle 68 / 73
At this point I get a bit lost....
Plus all the 3 piece propriety BMX / DJ stuff...19mm axle Vs??