Everyone, it seems, loves a good sequel. I know this because Iron Man 3 grossed something like $700 million in its first week of worldwide release, and that is a hua of a lot of money to make in a week. And because of my many years of film industry experience, I can state, as fact, that this number isn't going to get any smaller over the next few weeks.
I also know, through my finely tuned industry nous, that when there is this amount of money for a film with the number 3 in the title, there is bound to be a number 4. In fact I'm sure if Robert Downey Jr should decide not to do Iron Man 4, he will be bundled from his mansion in the dead of night, with a bag over his head, and taken to the Hollywood equivalent of Guantanamo, where he will be tortured by the producers until he agrees to do the film.
But if, for some reason, Downey doesn't do Iron Man 4 - like if he dies during a water-boarding session - then at least there is a source of many potential Iron Man sequels right there, at the producer's fingertips, in the form of a little thing called the Periodic Table of Elements.
Yes, because iron (Fe) is both an element (#26) on the Periodic Table of Elements, and also the name of a superhero in an action picture franchise, it is entirely feasible (to me at least) that any element on the periodic table should be able to spawn a superhero.
Magnesium (Mg) Man, for example, would be an awesome and very visual superhero. He could fire flare-like balls of light from his fingertips. Of course, his tendency to self-combust when wet would make him a very dry-weather action hero and completely useless at fighting a submarine-based super-villain.