Voadam
Legend
In 2e classes devoted to gods could be further specialized by specialty priest classes each tailored for individual gods or concepts. This was sort of the high water mark of diversity of specialized classes devoted to supernatural powers. Complete Priest Handbook, Legend & Lore, Faiths & Avatars, Powers & Pantheons, Demihuman Deities, Monster Mythology, From the Ashes, and a number of others provided lots of specialized classes.
Dragon magazine in 1e had the Death Master as devotees of Orcus.
2e Maztica had the Eagle and Jaguar knights for their specific pantheon in a similar niche to paladins.
3e I believe the OGL Book of the Righteous and Arcanis had individual classes tailored to the specific gods of their pantheons for both cleric and paladin roles.
Dragon magazine in 1e had the Death Master as devotees of Orcus.
2e Maztica had the Eagle and Jaguar knights for their specific pantheon in a similar niche to paladins.
3e I believe the OGL Book of the Righteous and Arcanis had individual classes tailored to the specific gods of their pantheons for both cleric and paladin roles.