The Lorwyn Five are a group of 5 planeswalkers.
They were originally intended to be released in the Future Sight set, but was moved into Lorwyn due to the overabundance of card mechanics in the former.
Each planeswalker is a single color card.
This possibly also led to the eventual team known as The Gatewatch, another group of monocolored planeswalkers who protect the multiverse.
List of Planeswalkers