Yoc, you're quite right, Richard loved excavating these really obscure characters.
As for the Turkish movies, there are a number of them with versions or mash ups of various superheroes. The one on here with Cap. and Santo is famous - or infamous - for having an evil Spiderman. Other heroes in these trash movies include versions of Spy Smasher; Superman; a mash-up hero combining bits of Cap Marvel and Superman; The Phantom. There is an original - or at least I think he's original - hero, The Pirate, in the film, "Demir Pence Korsan Adam". This one features Fantomas as the villain. It's here:-
https://www.youtube.com/watch?v=pC6lh6rSyHcbut be warned, it's violent and sleazy.
But it doesn't end there as there are non comicbook heroes from other countries. Mexican cinema turned out La Mujer Murcielago - The Batwoman:-
https://www.youtube.com/watch?v=pUyZB_xbG2cas well as a lot of masked superhero wrestlers.
Here in the U.K. we had "My Hero", a comedy superhero show with Ardal O'Hanlon - Father Ted, Death in Paradise etc - as Thermoman:-
https://en.wikipedia.org/wiki/My_Hero_(British_TV_series)
There is also The Black Commando in the movie serial, "The Secret Code".
Europe produced a few others apart from The 3 Fantastic supermen, and there were a few follow up movies. L'Uomo Puma - Puma Man, was made in 1980.
Flashman from 1967 was a joint Italian/French production:-
https://www.youtube.com/watch?v=u7tn6POvNs8Argoman/Superargo had a short series of films:-
https://www.youtube.com/results?search_query=argoman+superargoThere are also some Japanese heroes in film and anime but as they are a somewhat more adult orientated, I'll leave you to search them out yourselves. Try Kekko Kamen and The Iron Woman.
My post is very incomplete but this is absolutely intriguing and there are more if you want to look. The Philippines made some real shockers.