So, with the aid of the good folk on the Fantasy-Faction facebook group, I've compiled this list of popular fantasy books below 100,000 words just for you.
I've gone down to 15,000 words which is where a short story becomes a novella. Technically, books begin at 40,000 words.
Sixth of the Dusk - Sanderson- 16,000
Legion - Sanderson - 18,000
The Knight of the Swords - Moorcock - 28,000
The Emperor's Soul - Sanderson - 32,000
The Slow Regard of Silent Things - Rothfuss - 32,000
The Builders - Polansky - 33,000
The Lion, the Witch, and the Wardrobe - Lewis - 38,000
Thief of Always - Barker - 38,000
Nine Princes in Amber - Zelazny - 48,000
Elric of Melnibone - Moorcock - 48,000
Alanna: The First Adventure - Pierce - 49,000
The Ocean at the end of the Lane - Gaiman - 50,000
Stardust - Gaiman - 50,000
Mrs Frisby and the Rats of NIMH - O'Brien - 53,000
The Gunslinger - King - 55,000
A Wizard of Earthsea - Le Guin -57,000
Keturah and Lord Death - Leavitt - 63,000
The Armoured Saint - Cole - 63,000
The Last Unicorn - Beagle - 68,000
Storm Front - Butcher - 70,000
The Colour of Magic - Pratchett - 73,000
Harry Potter and the Philosopher's Stone - Rowling - 77,000
Prince of Thorns - me!!! - 82,000
Half a King - Abercrombie - 82,000
Dragonflight - McCaffrey - 84,000
The First Book of Swords - Saberhagen - 85,000
Sabriel - Nix - 90,000
The Queen's Poisoner - Wheeler - 91,000
The Princess Bride - Goldman - 91,000
The Last Wish - Sapkowski - 91,000
The Hobbit - Tolkien - 95,000
Neverwhere - Gaiman - 99,000
Where the number is green it indicates a children's book.
Where the number is bold it indicates a standalone book.
More on book length in general and word counts for my books in particular ... here.