Guns that "shoot better than they should".
You know, the kind of stuff that you didn't expect much from before you shot it, but proved to be real gems.
I'm lucky enough to have a few, which I stumbled across here and there over the years.
For handguns, I'd say it's my Taurus 96. Much better than expected (or paid).
For rifles, either a FrankenRuger 10-22 or an old Marlin-made Sears bolt .22.
And to sneak in a .22 air rifle, I have an RWS springer that turned out to be much more than I bargained for.