If you want the Lovecraftian mythos to be a thing, then the field of chaos magic (popularised largely by Peter J Carroll in Liber Null and Psychonaut) is an int

If you want the Lovecraftian mythos to be a thing, then the field of chaos magic (popularised largely by Peter J Carroll in Liber Null and Psychonaut) is an interesting one. For traditional ritual/ceremonial magic The Heptameron is possibly the easiest of the old grimoires to read, and whilst he has his detractors Joseph Lisiewski's Ceremonial Magic & The Power of Evocation is pretty readable as a modern take. (None of this is to comment on the truth or practicality of the belief systems and practices, it's just a pointer to possibly interesting early stage sources.)