Originally Posted by
Tacosnape
Things that help against Zoo:
1. Mogg War Marshal
2. Swords to Plowshares
3. Not playing Goblins.
Seriously, though, the tempo here is everything. You can play a long game with Zoo if and only if they don't damage you too badly on your way there. A single War Marshal can act like a 9-15 point lifegain for 1R if it triple chumps while you stabilize and ramp up goblinage. There's absolutely no way for Zoo to prevent War Marshal from doing what you want it to do very effectively - buy time. If you don't maindeck War Marshals and you anticipate Zoo, they're seriously worth taking a look at for a sideboard option.
I've also found having a 1-drop removal spell helps tremendously. Swords is very multi-talented here. It clears their 1-drops (So Nacatl won't thwack you for four on turn two when Pridemage exalts him), clears their blockers, and clears them permanently, which is more than any other option of removal can guarantee.