Sorry had a bunch of jobs over time, some probably pretty surprising for the most iconic Dark Lord in fantasy.
During the time of the Hobbit he was the Necromancer, which doesn't involve that much dabbling with undead - although keep in mind before our moden idea of a guy who raises spooky scary skeletons, "necromancy" was just a form of divination which involved the summoning of evil spirits, sometimes to pump them for information. The suffix "-mancy" just meant "divination", so as haruspicy means divination by looking at entrails, necromancy meant divination by spirits of the dead and pyromancy originally meant divination by looking into flames, which is a lot more boring.
During the Second Age he was disguised as Annatar, Lord of Gifts, who will probably show up in the new Amazon show as some sort of twink.
Before that when he served Melkor he was the Prince of Werewolves (werewolves here just being giant demonic wolves with poison fangs rather than your classic shapeshifters - although Sauron could turn into one, as well as a "vampire" which in the text seems to be a giant evil bat with acid blood).
Before he fell to darkness Sauron's original name was Mairon, and he was a servant of Aule, the Craftsman of the Valar and creator of the dwarves. Mairon and Curunir (later known as Saruman) were both servants of Aule, actually.
And if you want to get meta, in the earliest draft versions of the story the role of Sauron, Prince of Werewolves was served by a character named Tevildo, Prince of Cats. Yeah.