"Fantasy is a tricky genre to define, as it frequently overlaps with romance, sci-fi, horror, and more. Fantasy, in some form, has always been part of world literature. From One Thousand and One Nights (sometimes called The Arabian Nights), Beowulf, and The Odyssey to other myths and epics, magical and supernatural elements in literature are timeless and universal, but they aren't strictly speaking part of the fantasy genre. Most critics also consider magical realism a separate genre from fantasy, despite some similar elements.
Although I've personally enjoyed many of these books and series, I tried to explain how they were influential in both positive and negative ways and criticism they've received. Also, saying one book helped pave the way for others doesn't necessarily mean one author directly imitated another. More broadly, the earlier book's popularity contributed to an environment where books on similar themes would sell. These books have had major impacts on the fantasy genre"