Perhaps more mechanically conventional, Amy Rose and Miles "Tails Prowler" offer strong choices for Equipment and Vehicle decks, respectively
It usually kills most of the creatures attacking you, which means that the spells high mana cost can be worth it at times
Play these cards because they are powerful in their own right or play them because they do something your build wants
Alternatively, you could always buy some Battle Partners booster boxes from eBay or Zatu Games in the US and UK respectively
Thats why Sarevok is so interesting with Raised by Giants: Golgari punisher decks dont really exist at the minute
While I had positive experiences playing with Key to the Archive (and then later against it, once I knew its possibility space), my experience overall has made me less interested in playing with more draft/spellbook cards