Well, I've been digging through a lot of demonology-inspired fiction lately, and the 72 demons of the Ars Goetia show up more than you'd think, though rarely as a single central character. The thing is, 'central' is tricky. Is it a book about one of them, or just where one is a major player? For a deep cut, 'M.L.N. Hanover's 'The Devil Inside' series (first book is 'Unclean Spirits') features a protagonist who gets possessed by a demon, and the lore heavily references the Ars Goetia, with figures like Beleth and Raum being key. It's more urban fantasy than horror, which is a cool twist.
Another obvious one is 'The Lesser Key of Solomon' itself, but that's a grimoire, not a novel. For fiction where one is essentially the main character, I'd lean toward comics and manga sometimes. 'The Demon Ororon' by Hakase Mizuki plays with the concept, though it's loose. For a more modern take, Richard Kadrey's 'Sandman Slim' series has the protagonist battling through a hell filled with Goetic demons, and some, like Azazel, are pretty central to the plot. Honestly, most stories use them as powerful side characters or antagonists, like the demon Marchosias in some paranormal romance I vaguely remember. The challenge is finding a story where the demon's perspective and journey are the whole point, not just its role as a threat or a power source.