I try not to over complicate things. A tube, a CO2 cartridge, an inflator, and a set of tire levers. Granted, I kinda bank on not flatting twice in a single ride, but that has never been a problem for me. If worried about that (extra long solo ride in remote regions) I’d stash an extra tube and CO2 in the jersey pocket.

i also carry a tire boot, but it works no better than a dollar bill or shot block a wrapper.