This is similar to the Boros one in the fact that it is all about creatures. This one is green and white and is slower than Boros but has bigger creatures. The main ability is called "Convoke" which lets you pay mana costs by tapping mana (like normal) and creatures. This lets you play bigger stuff faster. You don't necessarily need 7 mana for the bigger Siege Wurm (5/5 trample), you can use 4 mana and tap 3 creatures to get it out!

In the next set, Ravnica Allegiance, this pairs well with:
Gruul (Green / Red)
Simic (Green / Blue)
Azorious (White / Blue)
Orzhov (White / Black)