What are some popular eras or genres of old comics that are highly collectible?

Golden Age comics (1938-1950s) are highly collectible, especially those featuring the original versions of iconic superheroes. Silver Age comics (1950s-1970s) saw the rise of many modern superheroes. Bronze Age comics (1970s-1980s) and early Modern Age comics (1980s-1990s) also have valuable issues, particularly those with significant story arcs or character developments. Key genres include superhero comics, horror comics, and science fiction comics.