It's tough to put a precise figure on it. The Fantastic Four franchise has a rich history of comic book releases. There are countless regular issues, spin-offs, and limited series. So, there could be thousands when you consider everything.
Certain variant covers or signed copies of Fantastic Four comics can be valuable. Issues that introduce important characters or have significant plot developments often command higher prices in the collector's market.
It's subjective. The Fantastic Four has its fans, but there are many other comic series that are also highly regarded. It depends on what aspects of a story you value most, like character development, plot complexity, or art style.
Fantastic Four wasn't the first. Marvel has a long history of comics, and several series came before it. Different characters and storylines were introduced earlier that contributed to the Marvel universe's foundation.
One of the best is 'Fantastic Four: The Coming of Galactus'. It tells the epic story of the Fantastic Four facing the devourer of worlds, Galactus. The art in this graphic novel is stunning and really captures the grandeur of the cosmic threats they face.