(Isochron Scepter)
After spending some time with the game for the past couple weeks, I think one of the sorest points it has against it right now is that you can collect a decent percentage of the cards within the game pretty easily and quickly, making it less enticing to open new card packs
Razorfield Ripper rewards you for collecting ever more energy counters, increasing in power and toughness based on how many are in your reserve when it attacks
However, if a card has been reprinted and appears in an eligible deck, any version of that card will be legal to play
TLE has a high profile of reprints considering the free Commander spells, tutors, and more, so these dominate the list
If X is 10 or more, return all creature cards from your graveyard to the battlefield