In the Temple of Nodens the Dream Elves speak of other Gods and cults that ruled Marmo in the past.
Boccob - Neutral God of Magic
Boccob is not so much worshipped as fed. Every spell cast, every new spell created, every magic item destroyed adds to his being. It is said that if a magic user dies with spell still memorized then his mind becomes part of Boccob.
Donblas - The Justice Maker Lawful God of Life and Order
In the past Donblas had a cult on Marmo but the last of his known true worshippers were slain two centuries ago. The body of Donblas is buried somewhere in the Underworld.
Istus - Neutral Goddess of Fate
The elves know very little of her and her cult. They believe that dreams can thwart fate.
Arawn - Lawful God of Death and Revenge
There are legends that this god will trade a living soul for a dead one of equal value.
Nergul - Chaotic God/Goddess of Death and Entropy
This god of course wants to unravel the universe and consume it inside himself as one big ball of chaos. It births monstrosities from a cosmic womb and mutates its worshippers before consuming them or mating with them.
Nodens - Neutral God of Death and Dreams
Obviously the coolest god according to the dream elves, he rules over the land of dreams where memories and lost souls drift like wreckage in a sea of ether. Death is a dream that lasts for eternity and he is the monarch of dreams.
Priapus - Chaotic God of Fertility and Change
No one on earth worships this god, probably. You do run into his statues in the land of dreams.