The most important intangible tools for gunsmithing are probably patience, mindset and the ability to look at a problem with a detached view. I’m not an expert but have many acquaintances who are, and have seen people screw things up.
Now you can have those but you still need the physical tools.
Things I have found useful.
Metal Nicholson files: would prefer grobet but can’t afford them yet.
Sandpaper: 220 grit to 6000 grit
India stones: 400-600 grit
Punches of various sizes
Brass hammer so as not to mar finish
Big rubber mallet: for when force needs to be mixed with finesse (very rare)
Armorer block: to support work when driving pins out
Drill press: haven’t used it for any gun parts, but can be used for making jigs to hold things
Drill press vise: for holding things in the drill press
Vise: removable padded jaws help me not damage parts
Calipers: Starrett for measuring things with precision
Sharpies: for marking material to remove
Things I will avoid at all cost
Dremel: fastest way to remove too much
Edited to add, and mentioned below:
Hollow ground screwdrivers: wood screwdrivers mess up the screws.