For an example of Subsupermen, see my avatar thingy. Some years ago I started a project to list, for my own info. and enjoyment, you understand, obscure masked mystery men and costumed heroes. I suppose many of them fall into the category of Subsupermen. Using Rovin's Encyclopedia, I tracked down American characters not included there and lots of British and European heroes. It rapidly became clear (after opening the Pandora's box that is Spanish comics and some other slightly less densely inhabited comics cultures) that there were hundreds, perhaps lots more, masked men out there. This is not a duplication of Vandal's Superhero index, just a simple personal project with quite tightly observed qualification criteria. Good fun to do. But I don't fancy trying the competition on hiliowbrow.com. A propos of hilowbrow, I notice he mentions The Black Terror and suggests it faded away. But, although never regaining the popularity enjoyed in the G.A. the character has continued to be published in some form or another , reprints and original stories, into the new millennium. (The Brereton issues sold some copies as did the Alan Moore stuff with The Terror). I only point it out as I'm a huge Black Terror fan.
Superheroes are a bit daft if you think about it too much but, as with much speculative fiction, a certain willingness to suspend disbelief is required, and no bad thing either.
Currently working on Circulo Justiciero and the heroes of Cosmos, both Spanish titles from a few years back. They're a bit too recent for me but I like the look of a couple of them.
Also intriguing are the Phantom style heroes that have turned up over the years in various places, who take off the legend of The Ghost Who Walks. Or is this just a wee bit sad?