I’d say it depends on the type of bike and tire.

Tubed or tubeless? For tubed, I’d recommend 1-2 spare tubes put in a saddle bag or one of those fake bottle kits that mounts in a bottle carrier, a small co2 pump, a few cartridges and a tire lever if yours are not easy to remove and install by hand. If you have a flat, replace the tube, then patch old tubes at home. For tubeless I recommend the dynaplug tool, optionally a small bottle of extra sealant and a valve tool. Small hand pump as co2 can interfere with tubeless sealant. I ride tubeless and just chuck these items in a jersey pocket.