Loa of kings, Rezan was the symbol of leadership and strength for the Zandalari peoples since the earliest days of the empire. His essence was consumed by the Prophet Zul in an effort to perversly[sic] resurrect the first king of Zandalar.
Serpent god of the Drakkari. Sseratus was worshipped for millenia[sic] until the day his own prophet slew him to consume his power.
For ages, Tharon'ja was the trusted guardian of Drak'Tharon Keep and patron of those who defended the borders of Zul'Drak. Tharon'ja fell to trechery[sic] when the threat of the Scourge and the lies of the Lich King drove his own followers to turn on him.
The grand rhino of Zul'Drak, he fell to the power of his own followers.
Mighty mamoth[sic] of Zul'Drak, he was turned on by his own followers who sought to take his power in an effort to survive the invasion of the scourge. When confronted, Mam'toth took his own life, and in so doing, took the lives of many of his would be slayers.
The Bear of the North, Rhunok was betrayed by his followers who wished to sacrifice him for his power. To prevent this, Rhunok turned to the power of a travelling adventurer to end his suffering and deny his followers the power of his death.
Wind serpent and a loa of great cunning. Quet'zlun met her demise at the hands of her own prophet. In her death throws, the loa of cunning claimed the souls of her trecherous[sic] followers, condemning them to a new underworld she had crafted just for their torment.
Elortha no Shadra
The God of Spiders, the Mistress of Spies, the Venom Queen, Silk Dancer, Death's Love. Elortha no Shadra has known many names by many tribes. The web of her followers stretched long and far.
The great bat, worshipped by Darkspear and Gurubashi alike. Hir'eek was revered by many. So it was with great mourning when he fell under the corrupting grip of G'huun the Blood God. Lost to all hope of redemption, Hir'eek was eventually slain by <name>, champion and speaker of the Horde.
The Hakkar tablet used to state that Hakkar was "defeated during a union of Zandalar with the Alliance and Horde" when Chronicle Volume 3 established that it was Zandalar and the Horde that defeated him. This was fixed during beta.
These beings possessing a plaque in the House of "the Lost Loa" may imply that these loa are dead for good. While as much was assumed for some, such as the Drakkari loa who were sacrificed and had their essences consumed, the following loa have a plaque despite the fact that:
Hakkar did survive his encounter with Jin'do the Godbreaker, and smote the troll after he was freed by the adventurers, telling them that he would "deal with [them] another time" before returning them to the physical plane.