I am unfamiliar with a lot of Superman comics, and yes I realize they are a bunch of murderers and worse, but finding out your entire world and even species is gone can have a way of making you rethink your life.
Have they ever realized there are some Kryptonians tucked away, that could find a planet to rebuild on and start having babies?
I haven’t the foggiest since I know almost nothing about comics but doesn’t the existence of Superboy and Supergirl suggest that there are more non-phantom zone Kryptons than we were led to believe originally?
The “tucked away” Kryptonians scenario was the genesis of a story arc a year or so ago where Argo City, a Kryptonian city shrunk to water cooler bottle size by Brainiac was re-expanded to a manufactured planet in the earth -sun (Sol) solar system.
Some elements were quite interesting. The take on Kryptonian culture (and there have been many such “takes” over time) in the story is that while it was technologically advanced, it was a somewhat rigid hierarchical, and politically borderline fascist state. Without being spoilerific this did not bode well. The unsatisfying end of the story arc was very ham handedly done IMO.
Kandor, not Argo. Parts of the population of Argo were incorporated into Kandor (noteably Supergirl’s parents), but it was Kandor that Braniac shrunk and kept.
And, no, since Kandor was introduced before Supergirl (albeit, not by long), her presence doesn’t actually significantly increase the number of known Kryptonian survivors (though, in current continuity, since it doubles it, she does - I doubt it’ll be long before we see Kandor again, though).
Superboy doesn’t increase the number at all, since characters under that name who are Kryptonian are Clark as a kid, and the ones that are separate from him are either unrelated (the original Reign of the Supermen version of the Kid), or cloned from him (the post-Hypertime version, and the current one - both also have human DNA to get past the fact that Kryptonian DNA is not properly cloneable).
Aren’t the Daxamites (Mon-El’s people) Kryptonian colonists? So they’re a whole planet-full.
Yes, Daxamites are descended from Kryptonians…on the other hand, they’ve been separated so long as to have evolved into a related species, rather than being Kryptonians - specifically, Daxamites have no particular response to kryptonite, but have rapid, deadly reactions to even tiny amounts of lead.
Back in the Silver Age, Jax-Ur helped Superman defeat Black Zero, who (in an unfortunate Ed,und Hamilton-written episode) was declared the being responsible for the destruction of Krypton: