Hearthpwn

Proof was wanted in comments so here is a screenshot of HS deck tracker

First of all, the 79% win rate is likely a massive high roll on a small sample size, but none the less here it is.

Zoo has improved a lot since sacrificial pact Nerf and several demon hunter card Nerfs. I think it is Zoo's time to shine and I wouldn't be surprised if it is a tier 1 deck in some form or another in the coming weeks. 

I wont bother with mulligan guide, there are other Zoo decks using the same Imprisoned Scrap Imp / Hand of Gul'dan shell, and they have done a good job with mulligan guides. Here is my explanation on cards that may be different in my deck compared to the others:

Frozen Shadoweaver - This card is very good in this deck as it allows you to slow the opponent while piecing together your board. It allows you to come back on board after your Imprisoned Imp buffs. It is also great for freezing Demon Hunter's face, stopping all of their cards that benefit from having their hero attack. 

1x Magic Carpet - I feel like magic carpet by itself is not a very good card without a hand full of 1 drops. and so drawing two of them into your hand can make you fall behind on tempo. So having 1 is nice as a way to get those 1 drops into action faster, but two is overkill. 

2 x Mortal coil - Galakrond warlock is still a thing, and they have 1 health minions galore. Also, even though Hand of Gul'dan is a great draw engine, we need a way to improve our chances of cycling into it. Sure it is anti-synergistic with Imprisoned Scrap Imp, but I feel the extra deck cycle outweighs the negatives. 

History Buff - 3 mana 3/4 body that buffs cards in your hand as you play minions. This fits the theme of the deck. Quite often I end up with very threatening 1 drops without having Imprisoned Scrap Imp just because of this card. it is also a threat that quite often takes removal over your bigger bodied minions. 

Maiev Shadowsong - this card is very valuable. Most of the time you only need two turns to end things with this deck and so this card shuts down any attempt to block that face damage. Also really nice against res priest, shutting down their cards that they want to resurrect, making them have to stall turns. 

no Fiendish Servent - I feel like this card could be great in this deck. Being able to pass buffed attack onto another minion is a way to keep high damage rolling. Truth be told, I can't afford the adventure to obtain this card. Include it if you want, but I think the other 1 drops are comparable with this. 

Anyway, I hope it helps some people reach legend.