The novel by William Beckford named Vathek is a Gothic/Arabic hybrid published in the 18th century about a power hungry Caliph who attempts, with the help of his equally twisted mother, to gain supernatural powers. Truly twisted and it influenced Lovecraft.

George du Maurier' Trilby is worth a read as it introduces Svengali to the world.

And let us not forget the godfather of American Gothic, Charles Brockden Brown's Wieland, which flirts with the supernatural throughout, but in the end its mysteries are solved in Ann Radcliffe-like fashion.