FSA has a bunch of axle standards.

Square taper
ISIS spined
MegaExo(Omega)
MegaExo
BB30
BBRight
BB386

MegaExo that is not Omega uses a 24mm axle, and is sort of compatible with Shimano BBs which are cheaper, lighter, higher quality and last longer. You might need the blue o-rings, and it is a pretty tight fit. It's not an easy slip fit.

BB30 will not work with anything but a BB30 frame. This will not work with BSA because the axle is only long enough for internal bearings inside a 68mm BB shell.

BB386 has a 30mm axle, but will work with a BSA frame with the appropriate bottom bracket. This is because the axle is longer to allow for 86mm spacing, the width of external bearings outside of a 68mm BB shell.