I have a small maybe 10 piece? metric Craftsman set I keep in my trail tool box. In the garage I have a complete Matco set.
Big thing is to practice using them a little before you have to. Cutting oil is a must to prevent damage to the tool and item. Motor oil works on the trail. And patience. I broke my M6 tap yesterday working on a project here at the house. Simply trying to cut too fast without enough oil. My fault.