Draconic Expanse

Tribal Convoke: Dragon (Your dragons can help
cast this spell. Each dragon you tap while casting
this spell pays for {2} or two mana of that
creature's color.)
Dragons you control have cascade and "When
you cascade with this card place all cards exiled
this way to the top or bottom of your library in
any order."
Draconic Expanse is and has protection from all
colors among dragons you control.