Mythology

Illustrations for Alexander Pushkin's "Fairytale of the Tsar Saltan"

Science Fiction

Pulp magazine

The cover of Weird Tales issue May 1934 featuring Queen of the Black Coast, one of Robert E. Howard's original stories about Conan the Barbarian.

Private Detective covers (above) by H.J. Ward

Conan by Bob Larkin

Conan by Boris Vallejo

Horror fiction

Tales of mystery and imagination by Edgar Allan Poe,

 illustrated by by Harry Clarke 

High Fantasy

The Lord of the rings by J.R.R Tolkien

 illustrated by Greg and Tim Hildebrandt

Fairy tales

Willy Pogany from Tales of the Persian Genii, 1917

Ida Rentoul Outhwaite (images above)

Mermaid by John William Waterhouse

… and by Edmon Dulac