Name any reasonably long-running action figure line using licensed characters -- especially superheroes -- and chances are, someone's made customized figures for the line, to fill in the gaps they perceived. The Mego 8" figures are popular for this, but so are Kenner's Super Powers line!
This custom Bizarro figure was obviously based on the Superman figure.
Here's a custom Gorilla Grodd... VERY custom created!
Next is this nice Metamorpho figure... I especially like the hand!
I especially like the Moebius chair for this custom Metron figure!
This is a nice custom Scarecrow, too... although I don't usually care for additions to the line that were already duplicated in later lines, such as the Batman and Superman animated series or Justice League ones!
Next up, some actual Super Powers toys! Here's a Hawkman stamp set, and I think I actually had one of these once upon a time! I'm not sure how many sets there were.
Here's a pretty cool Super Powers puzzle! You don't often see Superman, Batman, Green Lantern, and no other characters in any licensed product!
This Super Powers sleeping bag is pretty neat! No Green Lantern there, but Flash joins the usual Super Friends cast!
I don't know how many "Stain-A-Stickers" were produced, either... pretty neat, but I'm not sure I would ever have had the patience!
Here's the Wonder Woman Super Powers stamp set!
And last, but not least, paper plates, part of the party line!