The sooner you can get Gadget Hackwrench, Brilliant Boson in play, the better , since it will reduce the cost of all your Inventor characters and allow you to out-value the opponent on the board
If you want to spend a little more, you can also get one of three two-sided playmats, which is a nice touch as there are a fair number of double-sided cards in the Final Fantasy set
While there are plenty of other key reprints, such as Sorin, Imperious Bloodlord (for Rakdos Vampires in Pioneer), Bloodline Keeper only has 1 small reprint in the From the Vault: Transform
Glistening Oil Glistening Oil is best paired with Melira, Sylvok Outcast in a Golgari poison counters deck
You dont need them all, but you should strongly consider having a few of them
You can fill your deck with creatures with potent enter the battlefield effects and some good ways to bounce those cards back to your hand, or just have the most obnoxiously expensive creatures you can find and leave it at that