This is my first serious deck I'm building which I also want to use at fnm so I decided to go with some mono green devotion

Karametra's acolyte and nykthos, shrine to nyx will be the main ways to get mana, with the voyaging satyr to untap nykthos, shrine to nyx.

The plan is to get a couple of colossus of akros out on the field and to monstrosity them to send to the enemy and destroy them. Their indestructibility will be nice for counter spells, too. It shouldn't take too long to get one of them out if I have garruk out on the field.