Depends on what you mean by "long ride". Typically I have attached to all bikes, a pump or C02 tube, tire levers, bike specific multi tool, chain repair link, a few zip ties, nitrile gloves, some bandaids. That fits in a saddle bag.
On a tour, well, basically the same. May add a patch kit, extra tube, pump AND C02. That will take care of most issues, otherwise it goes beyond simple field repairs. Can't carry a whole tool box.

Edit: That's not ALL I take but specific to repair tools.