The Fionavar Tapestry (Guy Gavriel Kay): I quite enjoyed Kay's "Under Heaven", which was set in a fictionalized version of Imperial China, so I was curious to see his take on High Fantasy.
Unfortunately, Fionavar was written over twenty years before Heaven, and it is clear he wasn't nearly as mature as an author at the time. His critical failure here is that he didn't prune his ideas; it feels like he put every single idea he ever had into this book, and it's too much.
This book has light elves, dark elves, dwarves, giants, King Arthur, gods, half-gods, demons, nomadic horse riders, a Dark Lord, a High King, princesses, high priestesses, wizards, Dave, seers, sea monsters, tavern wenches, dragons, unicorns, spirit animals, ancient evil, isekai, magic tiaras, magic rings, magic daggers, magic stones, magic forests, force fields, ghost ships, the Wild Hunt, cursed lands, exiles, necromancy, resurrection, telepathy, teleportation, drought, and endless winter.
That's just off the top of my head. I probably missed a few. The book was 774 pages.
I wouldn't say this book was particularly bad, but it was often a slog to get through, and I can't say I recommend it.
I should have checked the rear cover of this book before I picked it up. I have a rule: Don't read a book with Tolkien's name anywhere on the cover, unless the book was actually written by Tolkien. Oops.