This could very well be the foundation of a new casual sub-format in Legacy: no blue. I have five shells, for each of the ABU lands for which I have a playset. These are the color pairs that don't get much competitive play. Green gets Elves, Red gets burn, often as Goblins, Green/Black gets Dredge, Colorless gets artifacts, and then there is Blue, which gets everything else. This is why Bayou, the Green/Black ABU land, and the four 'Blue and some other color' lands are the most expensive ones. Without further ado, here are the shells.
1. Badlands (Red/Black)
2. Plateau (White/Red)
3. Savannah (White/Green)
4. Scrubland (White/Black)
5. Taiga (Red/Green)