Hardened Scales is a great way to bolster the +1/+1 counter theme, and ways to play lands from outside of your hand like Radha, Heart of Keld can ensure even more landfall triggers
But I want to run this with a card from the main Final Fantasy set, Esper Terra
And while she's the hardest to be shut down of the three, if Feather is shut down then the deck falls apart
The second set also has some pretty interesting cards, such as Seymor Flux , and a spell that may be the perfect answer to the Jumbo Cactuar Extermination
The same is true for first strike, double strike, deathtouch, hexproof, indestructible, lifelink, menace, reach, trample, and vigilance
How about playing fair with Bitterblossom, Fiend Artisan, and Deaths Shadow all working in concert with one another