Now, I assume by the "Big 3" you mean control/aggro/midrange. Good to know you want to keep those balanced, but what about more niche strategies?
Here's a few to ponder on:
Tinker
Reanimate-or
Cheatyface (Show and Tell, Eureka)
Wildfire (Check out my primer!) :P
Ramp
Blue Aggro
Pox / Stax...