You know, this is a pretty hype casual deck. However, I feel that you are missing the biggest powerhouse for auras ---
Kor Spiritdancer .This girl is an Aura Gnarlid on steroids. The additional +1/+1 for each aura makes a huge difference and the card draw is forget about it! She will give you the reach to win every game.

Thank you for the suggestion, Nunn. I do not know how I overlooked that card. The +2/+2 for each Aura on it is nice, and card advantage is powerful. The draw could help me to draw necessary land and/or to play more threats earlier in the game. I will definitely consider adding a couple to the deck.

The thing that I really like about the Aura Gnarlid is that, once it's power is greater than the power of your opponent's creatures, it is essentially unblockable. In addition, It gets buffed for every aura on the battlefield. The Kor Spiritdancer only receives a bonus for each enchantment attached to it. Lastly, the Aura Gnarlid is green, so the Shield of the Oversoul can make it indestructible.

Thus, the Gnarlid is still very valuable in this deck. Hmm... what to remove.

Just wanna say... I copied your deck onto Cockatrice and played vs. my two buddies, and this deck wrecked them. Haha. Thanks, I'm going to build a paper copy. As I play around with it, if I find any suggestions I'll pass em your way. Awesome deck man.

Thanks, it's come a long way since I first built it. I had to make it more beastly and mana-efficient as time went by to keep up with my play group. Barely play any more, but try to bust this one out every time I get that chance.

Well,this card was just spoiled today... haha.

https://mythicspoiler.com/iko/cards/colossification.html