I run a similar deck. My Creature base is 4x
Ulamog's Crusher, 4x Eldrazi Devestator, 4x Fangreen Marauder, and 2x
Fierce Empath to search up bigger threats.
Tree of tales is worth an include over forests in this package as you can
crop rotation it for 5 life with a Fangreen Marauder out. I have considered adding red to my build too, for a little bit of removal, potentially something like
Rolling Thunder or Kaerevek's Torch which can make use of your big mana.
Although they don't produce green, it is also worth considering Sejiri Steepe and
Bojuka Bog as lands.