General game plan

In a nutshell (pun intended), this deck is an infinite Greybough deck, where games go through stages. (Going forwards, I'm abbreviating Greybough to Gb, otherwise I have to write it as many times as you summon it.)

As with many druid decks, the early turns are quite passive, but I have less ramp than normal because it is a highlander deck and Prince Taldaram means I couldn't have any 3 mana ramp. Crystal Merchant acts as a pseudo-3 drop, and does a pretty good job of distracting opponents early on. Other early game minions and minion-summoning spells are there to double up as something to do early on and as tokens for Gb deathrattles later on.

// Note there probably aren't enough 5+ mana cost spells to justify [Hearthstone Card (Stell Beetle) Not Found], Garden Gnome and Groundskeeper. They were relics of an earlier build, but they performed well enough that I never got around to taking them out.

The next phase is stalling and drawing until you can play Gb along with one of:

• Germination
• Prince Taldaram
  • The prince is well worth the loss of other 3 cost cards. He either lets you get 2 Gbs out a turn earlier than Germination allows, or can copy a minion with a deathrattle to summon Gb(s). So he can add multiple copies to the board by himself.
• Ixlid, Fungal Lord
  • The best way to copy Gb since there is a third minion around to soak up the deathrattles, which is important to make sure the opponent doesn't slowly work through them all.

It is likely this wave either gets removed completely or is enough to win the game, especially after you add a third Gb to the board. If it gets removed, N'Zoth, the Corruptor is there to bring them back. Most of the time he'll resurrect 6 trees. Flobbidinous Floop is best used as a second N'Zoth, but can be used for Gb itself or Zephrys the Great if appropriate for the situation.

There are few decks that can deal with multiple waves of Gbs, even in Wild, but for those that can, Elise the Enlightened is utterly brilliant. Doubling N'Zoth, Floop, and/or the cards for the initial wave very often just means you have too many waves for any deck to handle unless they are built specifically to do so. If you are up against a control deck, it is important to hold N'Zoth or Elise in your hand until you draw the other.

The subtleties of using Greybough

(This is difficult to explain clearly. In the end experience is the best teacher here.)

Gb ends up being more skill testing than you expect because there is no such thing as an infinite board of Gbs, even in the absence of silence/transform/sap effects. The reason is that deathrattles occur in the order they are obtained, so a Gb's effect will trigger BEFORE it summons another Gb. So if it was the only one left on the board when it dies, you will lose it permanently.

If you have only 2 Gbs, this happens quite often, which is why it is useful to have Ixlid or other minions with them. When you have 3, the opponent can play well and kill the Gbs in an order to make sure one disappears, though it gets harder and harder for them to do this as more Gbs are added because all the deathrattles have to land on a single minion for it to work.

The reverse is also true: if you have 3 Gbs and they will all die when they attack, make sure to attack with the one who gains the deathrattle first. As a rule of thumb, always attack with Gbs that will summon more Gbs first, that way you shouldn't lose any.

Finally, you can protect against full board clears by trying to keep at least 1 Gb that will summon another when it dies. That one will then soak up some deathrattles when the board it clears. Note that how many it gets will depend of the order minions were summoned, so you are unlikely to save all the Gbs, but you can often keep a few around this way.

How many Greyboughs can I expect in a game?

If this were in Standard, not very many because few decks can deal with 1 wave let alone several. As a result, players often concede quickly against Gb decks in Standard, which is great unless you're trying to make progress on the 'Leaf Us Alone' achievement which needs you to summon 200 Gbs. That would take a very long time if you summon 3 or 4 in a game.

However, because it is in Wild, many decks run a lot of serious removal and have their own equally OP combos, so opponents are much more willing to persevere without giving up hope. As a result, I usually summoned about 10-20 Gbs in a game. I had one mammoth game against a Big Priest which went on so long with neither of us able to clear the other side's board the 4th or 5th time that I ended up summoning a crazy 99 Gbs in a single game. Hats off to that priest!