Fat fantasy series are generally
a) longer than 3 books, including different series set in the same world, or they are
getting there...
b) fat
AXIS
THOMAS COVENANT
DRAGON PRINCE
DRAGON STAR
FARSEER
MALAZAN BOOK OF THE FALLEN
Erikson, Steven
RIFTWAR
RUNELORDS
SHANNARA
SONG OF ICE AND FIRE
SWORD OF SHADOWS
SWORD OF TRUTH
WARS OF LIGHT AND SHADOWS
WHEEL OF TIME