If you already have a card with Start your Engines
Cheating out a Vein Ripper three turns before you like would have in a normal game sets your opponent back far too much in order to deal with it
Initially, I was focused on Winding Constrictor decks, since Winding Constrictor gives us two level counters for the price of one, but after working on a couple of different shells featuring the Snake along with Collected Company and Venerated Teacher, I finally gave up
Seems like a great card in the 99 of a deck, though
Spring-Leaf Avenger Spring-Leaf Avengers ninjutsu is reasonable enough at 4 mana, and youll get a huge 6/5 that hits with an Eternal Witness effect
While theyre perfectly handy cards to have in a game, collectors dont consider them highly desirable