A veritable bounty of aliens for your perusal.
People of Venus, the Jibbering Giant of Jupiter, Weird Inhabitants of the Strange Planet:
Blast Bennett has lost his little pal Red, and his solution is to just kind of bop around from planet to planet, asking random aliens if they have seen a red-headed guy. I've grouped these alien together because they all represent a very boring alien design trend of the 40s and 50s (and beyond!): the alien as just some guy. The Venusians are short, bald guys; the Jovian is a really big guy and the weird inhabitants of the strange planet are guys who could use a shower. (Weird Comics 004, 1940)
Ceresians:
During an unscheduled stop on then-asteroid/now-dwarf planet Ceres for water, Ted Hunt and Jane Martin, aka the Star Rovers, stumble into a conflict between the underground-dwelling native Ceresians and gargoyle-like invaders known as the Harpies.
This is a pretty classic setup! The planet full of generic white guys vs some horrible space monsters scenario is a surefire way to engender sympathy in an early 20th Century American audience! It does however leave you with some fairly uninteresting humanoid aliens - I do appreciate the seeming shift in Ceresian society from a Medieval to more of a Roman aesthetic as they are forced to abandon their castles for retrofuturistic bunkers, but that's about it. (Exciting Comics 005, 1940)
Harpies:
The Space Rovers make their way to the Harpy home on Asteroid Nunda and are almost immediately captured after being incapacitated by the thin Nundan atmosphere. They find that rather than being simple predators, the Harpies have an advanced society that places great value in both science and the democratic process. They are, sadly, complete Harpy chauvinists who don't recognize the
Ted and Jane escape this fate due to the Harpies' scientific curiosity about them, and manage to parley that into a successful escape attempt. Once back in their ship and armed with superior firepower, perhaps they will be able to force the Harpies to stop their vicious ways at the barrel of a gun!
Just kidding! As a nonhuman species who pose a threat to a world of white guys, the Harpies are of course fair game for utter and total annihilation - I'm talking blow up their cities and hunt down all of the survivors. But don't feel bad, because as Jane says, "they're nothing but enormous, blood-thirsty bats!" Now the Ceresians are free to go back to inventing feudalism or whatever. (Exciting Comics 005, 1940)
Lunaris:
The way I do these Alien Round-Ups is that the first entry is from whatever comic I'm reading at the moment and then I pluck the rest from a big ol' spreadsheet that I've been maintaining for years, which is why it's a pretty fun coincidence that the the next aliens on my list after the Ceresians were the Cold Men, who rule the surface of an unnamed icy moon while a race of white guys called the Lunaris hide in tunnels below. Once Ray Darrow, aka the Star Rover (another little coincidence there) stumbles into this conflict he of course sides with the noble Lunaris against the horrible Cold Men, and it doesn't hurt that the Lunaris Queen is somehow descended from Earth humans, so that Darrow can feel okay with being attracted to her, I guess. (Doc Savage Comics v1 003, 1941)
Cold Men:
Cold Man society isn't quite as fleshed out as the Harpies' was, but Darrow's conclusion is the same: to ensure the continued safety of the much more familiar-looking Lunaris, the Cold Men must be utterly annihilated - sure hope that the newly surface-dwelling Lunaris don't find the headquarters of some sort of Cold Man organization dedicated to fostering peace between the species or they might end up feeling guilty about their role in this genocide some day.
... I do like that the Cold Men seem to actually be made of snow or ice. (Doc Savage Comics v1 003, 1941)