Isperia has a unique and powerful combat trigger that lets you tutor up a flying creature, but you have to correctly guess a card in the opponents' hand -- quite a hoop to jump through
The Partner Paradox The creation of something resembling the partner mechanic was a huge when, not if for Commander
For example, a Grey Hunter unit has three different faction keywords, each representing a more specific faction than the one before it: Imperium, representing the entire human empire with its capital at Terra
Proliferation effects are also important, as are counter-doubling effects like Vorinclex, Monstrous Raider and Doubling Season
MTG Players are so excited about Final Fantasy that theyve already cleaned Amazon out, predatory product pricing be damned
Oh, and while we're talking about her, I've got to mention Sword of the Chosen - the sword of Selenia