6. Robin Hood
After King Arthur, Robin Hood is the most famous character from the British Isles. Characters like Little John, Will Scarlet, Friar Tuck, Maid Marian, and The Sheriff of Nottingham are ripe for adaptation—perhaps in their own spin-off stories. Robin Hood himself has been portrayed by the likes of Kevin Costner, Russell Crowe, Sean Connery, Cary Elwes, and Errol Flyn.
So it’s clearly been done. However, there’s always room to expand (or condense) the story to your own storytelling will.