Here is a list of Movies and TV Series based on Arthurian Legends. Includes Adaptations of the original Arthurian Legend, Tristan Legend, Sir Gawain and the Green Knight, A Connecticut Yankee, Prince Valiant, set in Roman Empire, Animated Films, Modernization and Parodies, Foreign Language. How Many have you Seen? Good Luck!
Also I know Arthur and the Invisibles isn't actually based on Arthurian legends but it still has hints: the main character is called Arthur and he pulls the sword from the stone.