Hey, don't listen to these clowns who give you stupid advice like running Abomination (knowing that you will be dead or near dead by the time you can actually play it).
The only way to beat Zoolock is to be lucky on mulls for an aoe OR go aggro and meet the Warlock head on, there's nothing else you can do. Therefore stock your deck with as many aoe options as you can, including Wild Pyros.
Taunts don't matter to Zoolock, so you might as well run other minions since they typically have better stats than Taunts for the same mana cost. The thing is, a Zoolock will always board clear whatever you play anyway, so having a taunt doesn't present any advantage. I guarantee if you play a minion, the Zoolock will focus on killing it right away before it can do anything, so when people say "run taunts" they are showing their ignorance since Zoolock is actually a control deck anyway. Instead of running a Taunt, you are better off running a minion that does something right away, such as charge or some other burst dmg. Even if you manage to get a big taunt on field, the Zoolock will easily blow it away with a Soulfire or Doomguard. A defensive deck doesn't stop Zoolock and it never did. It would have to be a MASSIVE taunt, like an 8/8 at least to actually slow a Zoolock down.
Again, defense is not how you beat Zoolock, offense is how you beat Zoolock. The exception to that is Priest, because they MIGHT be able to rebound using a great deal taunts and healing combined. If you aren't playing Priest, then there's no point in trying to defend a Zoo control rush, instead you have to overpower it. For instance when I play vs Zoolock with Druid, I go for the Zoolocks face more than trying to taunt up. If I taunt up, he will remove the taunt and still hit me all in the same turn because a Warlock can simply do more with the same amount of mana compared any other hero class. No other hero class can go for face AND board control at the same time like Warlock, it's nuts. IMO, Blizzard should make a change to how Warlock works. Tap should have a 1 turn cooldown and cards that discard (like Doomer and Soulfire) should be FORCED to actually discard, instead of the Warlock being able to empty their hand and THEN play the discard card without paying the price for it. Why should Warlock be able to do 4dmg nukes for free !? That's obviously going to lead to balance issues.