Landwalk theme: Most of the creatures have landwalk of some type.
Swords of X and Y; other ways to trigger off of dealing combat damage.
Ways to give land types to other players (unfortunately there are very few ways to do this in G/R). Usually not a big deal anyway, because each creature can usually attack at least one person and be unblockable.
Click here for a text version of this decklist
Click here for my EDH Commander decks