More like The Cursed Catacombs

anchored on:fantasymiddle gradesecondary worldunderground & caves

but

Narrow

NarniaUniverse
universe38 books1950
Portal fantasy.
“Once there is a wardrobe at the back of a spare room, and behind the fur coats the wood gives way to snow, and a lamp-post burns alone among the trees.”
from the catalogue
Start with The Lion, the Witch and the Wardrobe →
includes Narnia, Narnia Solo Adventures
Tolkien's legendariumUniverse
universe163 books1923
Fantasy, set in secondary world.
“Before the seas were bent and the mountains raised, there was Music — and from that Music came Arda, and in the west of Middle-earth the long defeat and stubborn hope of those who dwell there.”
from the catalogue
Start with The Fellowship of the Ring →
includes The Hobbit, The Lord of the Rings, The History of Middle Earth, The Fall of Gondolin, The History of the Lord of the Rings
ErithSeries
series4 books2001
Epic fantasy, about fae.
Start with The Ill-Made Mute →
The Old Kingdom / Abhorsen milieuSeries
series11 books1995
Start with Sabriel →
Howl's CastleSeries
series3 books1986
completed
Whimsical in tone.
Start with Howl's Moving Castle →
Tiger and DelSeries
series10 books1985
Sword and sorcery.
“Jennifer Roberson's fantasy series pairs Tiger, a desert-born sword-dancer from the south, with Del, a Northern swordswoman trained in her own tradition of blade-magic, as reluctant partners across a hostile borderland.”
from the catalogue
Start with Sword-Dancer →