https://deckbox.org/sets/746400

I'm working on it for a standard tournament (Game Day August 9). Any pointers would be awesome.

Thinking of getting rid of Urban Evolution, Fathom Mage, Archetype of Imagination, and Archetype of Endurance; anything I should add?

I've been up to my ears in mana (69 grey) through Kruphix, prophet of Kruphix combo. So any X/X green or blue spells would be magical for this time. (Mistcutter Hydras have been ordered, as has more temples of mystery, and biomass mutation; Hope they arrive in time (probably won't :P))

My gyre sage was at one time producing 7 mana thanks to bioshift and renegade Krasis. The playtest was against a red/green deck, the win-rate was low. But when I won it was completely ridiculous :P

For creature... add more hydra? Vastwood Hydra, hydra broodmaster, or Savageborn Hydra.
As non creature i recommend Into the wilds and primeval Bounty.