Holly Blake Universe

Start with The Cruel Prince.

Then read The Lost Sisters, a little novella that explains the actions of Taryn (Jude's twin sister) in The Cruel Prince.

Next is The Wicked King and The Queen of Nothing, that ends Jude's story.

Then read How the King of Elfhame Learned to Hate Stories, a little novella that follows Cardan.

Lastly, read the books of the Spin-off duology The Stolen Heir: The Stolen Heir and The Prisoner's Throne.