Let it never be said that Captain Marvel, the hero who graced the pages of Fawcett Comics in the 1940s and 1950s, was not influential in the hero genre. While he eventually phased out of existence for a couple decades, due to alleged similarities he had with a certain Man of Steel no not that one or the other one) and the threat of legal action from a Distinct Competitor, there was some merit to the argument that his own publisher should have gone after MLJ and later Charlton for copyright infringement.
MLJ's version of the Big Red Cheese (as Cap was known by his foes) was himself all dressed up in a predominantly red costume, with some blue trappings instead of yellow. Red Rube was more than a homage, he was and out and out rip off. Just consider, for example, the superpower delivery mechanism used to effect their transformations!
Seems that Steel Sterling ain't to happy about another character edging him out of his own title, at least on the covered. Alas we never seen a match between these two "Supermen" to see which was top dog. Still, the fact that you may never have heard of Reuben Reuben (no...that was REALLY his real name!) seems to indicate who ultimately won.
In the mid-50's, Charlton tried their own variation on Cap with a bit more of a twist. Nature Boy had a penchant for blue and yellow, although on at least one cover David Crandall's heroic alias sported an inverted red and blue look from Rube (bare legged instead of Rube's bare chested look).
The parallels between one another and Cap don't stop there. Each were separated from parents (Rube left an orphan, and Nat left at sea).
Each inherited superhuman abilities from a crowd of ancient heroes. However, while Red Rube's abilities, which he gained after saying "Hey Rube" were mostly physical (i.e. strength,durability, speed) and a smart noggin; Nature Boys gifts, which were derived from calling upon one of the "Kings" that bequeathed him his powers, were energy related (i.e. cold, heat, lighting, water, etc).
Oh and they were each a pair of blowhards. I mean literally. As in creating massive gusts of air pockets that projected them into battle.
And after their inaugural comicbook runs, Red Rube in Zip Comics #39-47, (starting in 1943) and Nature Boy in his self-titled book #3-5 (starting in 1956). There was a feature in Charlton Bullseye v1 #1 about Nature Boy, and what it conjectured what it would be like to have him meet Captain Atom. And there was a reprint by another publisher of one of Nature Boy's outings decades later by another publisher altogether. Yet for these two, they would remain on the comicbook sidelines forevermore, no doubt due to their unoriginality. Except in lame blogs.