I, like Sam & many others here have a pretty good selection of tools & such for gun tinkering,, (or gunsmithing for Sam & a few others.)
I have tools from Most of the known names & such, and also odd ones from wherever. From Snap-on, Brownell's, Wheeler, Chapman, Craftsman, MAC, etc.
But the biggest thing is learning how to NOT break a tool, or use it for a purpose it wasn't intended for.
Even the very best, top quality tools can break or bend. Yet,, properly used, a much lesser quality tool can do the job if the proper skills are applied.
Stuck screws? Use a penetrating oil to start with. Add heat and/or impact type of tool to break the stuck tension adhesion.
Biggest problem,, people get into a hurry trying to fix something. Soaking in a penetrating oil is one of the best ways to remove a stuck screw in general,, all while using the correctly fitted screwdriver blade, AFTER the oil has had time to work.