"The Good Witch of the West" manga series and the anime track pretty closely. There is more detail in the manga, for instance the "yuriness" is more straight forward with respect to Igraine, who becomes Firiel's knight, and there are more hints about lost technology in the world of the story.
Volume 5 starts just after Rune has left Firiel to travel South. Adele is given her queenly task and Eusis must go fight some dragons (dinosaurs, apparently) for the honor of Adele. Firiel follows Eusis south in search of Rune. Along the way, Firiel gets a baby unicorn sidekick -- oh, so cute!
And on to volume 6, which will come out who knows when ...