Welcome to the house that Tolkien built. Epic Fantasy (also known as High Fantasy) is the quintessential fantasy sub-genre, the fount from which all other fantasy sub-genres have flowed, and J.R.R. Tolkien’s elves and orcs and rings (oh my) utterly dominate the field. There are, of course, stand-outs and outliers, stories that forge news paths in an old sub-genre, but even when a tale isn’t filled with staff wielding wizards and subterranean, master-craftsmen called dwarfs anything called epic fantasy still contains a few essential elements that were originally established when Tolkien first fleshed out Middle-earth on paper.
Epic fantasies create entire worlds, with long and complex histories and vivid cultures and lifestyles. How complex and vivid? Tolkien actually created (or adapted) a historic timeline leading back to the creation of the world, myths, legends, deities, several races of creatures (many of which have become staples of the fantasy genre), multiple kingdoms, and an entire language for the fictional inhabitants of his world! If you look hard enough in the right places I bet it wouldn’t take too much effort to find someone that speaks at least passing Elvish. They are not all that in depth, but that is the kind of detail you are potentially looking at when you jump into an epic fantasy.
In case that isn’t enough to wrap your head around, epic fantasy also almost always has a large cast of characters taking part in quests and adventures that will affect the fate of an entire kingdom or world. Possibly multiple worlds.
So, it is a complex workout for your imagination and memory. What else?
It’s big. Aside from its often immense geographic scope, as it is not unusual for the cast of characters to have to trek across continents and cross oceans in the pursuit of their goal, these stories can also cover large spans of time, with years, decades or even generations passing by in the course of the story (or series of stories). They are also big in another way – these are not typically short books. Once you get sucked into an epic fantasy series you are in it for the long haul.
The Belgariad series by David Eddings
The Deed of Paksenarrion trilogy by Elizabeth Moon
The Hobbit and The Lord of the Rings trilogy by J.R.R. Tolkien
The Mistborn series by Brandon Sanderson
The Original Shannara Trilogy by Terry Brooks
The Sword of Truth series by Terry Goodkind
The Wheel of Time series by Robert Jordan