There is Old World of Darkness and New World of Darkness.
The original (old) World of Darkness had 5 games, each of which was a separate (but related) core game:
Vampire: The Masquerade
Werewolf: The Apocalypse
Mage: The Ascension
Wraith: The Oblivion
Changeling: The Dreaming
These are slowly, but very successfully being kickstarted into 20th Anniversary editions. Vampire was the most successful of the original games, probably followed by Mage and there was a drop off in sales after the ‘big three’ was released. Of the 20th Anniversary Kickstarter campaigns, Mage notably is the second most successful RPG ever (after Exalted) with well over $650,000 raised, although Vampire was released just before kickstarter campaigns became the fashion. I’d speculate had it been, it could have raised over a million.
Later, after a business and line rejig, they also added:
Hunter: The Reckoning
Demon: The Fallen
There was also a supplementary Mummy: The Resurrection, historical games (Dark Ages, Werewolf: Wild West and Mage: The Sorcerer’s Crusade) and a limited run Wraith spinoff - Orpheus.
New World of Darkness (which was also something of a marketing rejig) just has one core rulebook - The World of Darkness - with each of the various lines being supplemental:
Vampire: The Requiem
Werewolf: The Forsaken
Mage: The Awakening
Promethean: The Created
Changeling: The Lost
Hunter: The Vigil
Geist: The Sin Eaters
…and Onyx Path has continued with:
Mummy: The Curse
Demon: the Descent
and upcoming Beast: The Primordial.
Also, do note that although Onyx Path is publishing these books now, they are still licensed by White Wolf. Their business model is somewhat different to the normal game publishing model. Everything is basically PDF and POD.
