Have we found stable, super-heavy elements?
There already is an element, heavier  (higher atomic and mass numbers) than all naturally occurring ones, that is stable enough for everyday use.  You are probably using it, well, everyday, in your smoke detector.

It's americium, element 95, with three isotopes having 100+ year half-lives.  Americium-241 has a half-life of over 400 years, for americium-243 it's over 7000 years and there is even an odd-odd isomer, with mass number 242, having a half-life over 100 years.  (https://en.wikipedia.org/wiki/Americium).

This is not perfect (and whether it's called "superheavy" depends on definition), but the americium is out-lasting other components of smoke detectors, or industrial gauges where americium is also used.  In that sense we can indeed call the most long-lasting americium isotopes stable.