Aberdeen Bestiary
The Aberdeen Bestiary is a British manuscript showing know beasts of the medieval era, and fantastic ones too.
Book on the Properties of Things
The "Livre des Propriétés des Choses" ("Book on the Properties of Things") by Barthélémy l'Anglais is a kind of encyclopaedia from the 14th century.
Codex Manesse
The Codex Manesse is a German poetry / songbook also known as Große Heidelberger Liederhandschrift.
Great Hours of Anne of Brittany
The Grandes Heures d'Anne de Bretagne (Great Hours of Anne of Brittany) is a prayer book with hundreds of pictures of plants, trees and flowers.