Hearthpwn

This is  a deck that I thought of early on during the reveal time and it worked out pretty well so far. I am currently 8-2 with this deck and planing to play it further. The idea is to cheat out huge beasts with Oondasta and Stampeding Roar and get a big board state this way that the opponent is difficult to deal with. The Juicy Psychmelon helps to find all those beasts. Especially Ironhide Direhorn is pretty good with Stampeding Roar as it turned out. I also added Master Oakheart for another way to get big board swings. I choosed another package for Oakheart than the usual Dragonhatcher package, as this requires to play high cost Dragons and I have already many high cost beasts. The package of Tar Creeper, Mechanical Whelp and Witchwood Grizzly  is less powerful, but it turned out to be impressive enough in the games I played. Tar Creeper and Grizzly are also good defensive tools in the early game.

I will keep the guide updated and write a more detailed one at five upvotes.

edit: 05.12.2018

Thanks for the upvotes. I am now 12-5 with this deck with a winrate of 71%.  I played between the ranks 8 and 6.

Gameplan:

The deck is similar to the old big druid decks or Hadronox Druid decks. The difference to the Hadronox Druid, where you stall the game until you overwhelm the opponent with never ending armies of taunts, is that here you want to win a bit earlier. You stall the early game in the same way, but you win by creating relatively early huge board sates by cheating out large dinosaurs. The idea here is against slow decks to keep the board even and then put multiple big minions in the same turn into play so that it is difficult for your opponent to handle it and then snowball with additional big threads. Against aggresive decks you try to stay alive and use those huge tempo swings to get ahead on the board.

Card Choices:

The defensive tools are more or less the same as for each other slow druid decks. The advantage of the Tar Creeper and Witchwood Grizzly as your Master Oakheart targets is that they also help you in the early stages to keep you alive. There is a bit few removal in this list, though, so maybe this is something that can be worth changing.

The key cards for winning are Oondasta and Stampeding Roar coupled with big beasts like Tyrantus and Ironhide Direhorn as well as Master Oakheart. Especially Ironhide Direhorn is great with Stampeding Roar as it allows you to get two big bodies and remove one of the biggest from your opponent for only six mana. I wasn´t sure about the Direhorn first but it definitly convinced in the games I´ve played. 

Juicy Psychmelon is also a quite important card, as it ensures that you have enough gas and most importantly that you have one of the big board swingers in Master Oakheart or Oondasta paired with Tyrantus or Ironhide Direhorn. This is also a reason why I didn´t want to play Dragonhatcher, since then you are not guaranteed to draw Master Oakheart or Oondasta with your melon. Stampeding Roar or Oondasta might probably the only way that the melon works (in a non combo deck), since the downside of melon is that you loose tempo while playing it and get only a bunch of slow cards that you can not easily play with other cards in the same turn. This Tempo loss can easily be cancled with these two cards. On the other hand the melon (and the other card draw that Druid has) allows to play  card-disadvantage cards like Stampeding Roar.  However, the timing for melon can be tough sometimes, especially against aggro decks.

I play only one Ultimate Infestation since you have already many high cost cards and Juicy Psychmelon to draw many cards. But because it is so good I still wanted one. For the eight drop for melon I choosed The Lich King, as it provides you with a bit more value, if you need it, and is a big taunt. However, it is not so important and can be replaced with another eight drop (like Primordial Drake).

At building the deck I looked that the minions to pull out with Master Oakheart can not be drawn with Juicy Psychmelon as you want to draw the beast synergy cards and you don´t want to run out of Master Oakheart targets by drawing them with the melon. Tar Creeper and Witchwood Grizzly are great or good targets to pull out and they are also good in the early stages. Mechanical Whelp is not so good on his own, but probably the best two attack target that costs less than seven mana. What I like about it is that it gives you some kind of protection against board clearers which is quite important if your goal is to build big boards. Witchwood Grizzly is also a good target to cheat out with the beast synergy, especially if you also need to defend yourself.

I thought about playing Hadronox too, but it does not fit so well in the gameplan and it does not ensure you to draw Oondasta or Master Oakheart with your Juicy Psychmelon.

I don´t know exactly if two Juicy Psychmelon are necessary, as the second does very less most times and Druid has also other good draw effects. Maybe you can cut one for a Naturalize as you have few removal anyway.

Mulligan:

The deck mulligans very similar to the other Druid decks. Always keep Wild Growth. Against classes that tend to be slow, I would also keep Nourish and probably Juicy Psychmelon. Against aggressive classes I would keep the removal (Lesser Jasper Spellstone and Swipe) and Tar Creeper. Especially against Paladin Spreading Plague as this is your best card against odd Paladin.

 edit: 14.12.2018

I played the deck further and my record is now 24-8 with a winrate of 75%. I also played it in the Standard Brawliseum and went 9-3.