Hearthpwn

The Wild Ladder has never been this free farm before

Since playing Quest Warlock and/or Pirate Warrior inevitably causes brain damage, they both end up misplaying horribly and this deck is perfect for taking advantage. The remaining 1% of players on the wild ladder mostly don't matter. 

Edit: the ladder is slightly less free, because everyone realized this was the best deck in the format and started teching heavily against it. It still got me an early legend this month though, just 80% winrate instead of 98%. 

General Playstyle and Match-ups
If you've been playing standard, you might think this is a combo deck; it isn't. In Wild, this deck is an aggro deck, but with elements that allows for easy board control when facing faster decks. Although this deck can require some foresight, your decisions mostly comes down to whether or not to use a 3-mana spell. 

Generally against aggro: control the board with cheap damaging spells and your hero power. Aim to complete your quest and get on board with Tavish for a swing turn. Coin is tempo. Since tempo is essential, it might be worth using a 1-mana spell on the enemy hero on turn 2, if they don't have minions in play. This is to allow for a turn 3 hero power + 1-mana spell. Any (decent) aggro player facing this deck should be skipping turn 2, because it forces the quest hunter to waste removal on the enemy hero rather than on their minions. 

Generally against control: Precognition is key. Spam that hero power and use any of your damaging spells inside the red area. You aren't in a rush, but hand disruption can pose a huge problem if you're being too slow. Playing faster with this deck reduces it damage, but getting  Tavish down faster can be worth it sometimes. If you get him down on curve it typically wins the game. You can try to complete quest and play Tavish on the same turn but from my experience it doesn't seem necessary. Coin usually represents 3 damage and (most importantly) does NOT always need to be comboed with Tavish. A typical use it to complete quest on turn 4 by using coin, then playing Tavish on turn 5. 

- Quest Warlock: If you encounter the combo version of this deck often you can try out another Rustrot Viper to counter their weapon. Play around Raise Dead and don't make it easy for them to kill their Crystallizer. In this match-up specifically, the Sidequest almost always needs to be comboed on the turn you finish it (preferably with Powershot, but smaller damage can function as well - this does require some foresight so think ahead.)
- Pirate Warrior: Mulligan for cheap damage to control the board with. Their quest doesn't win the game as long as you keep up the tempo and they have very little reach to directly damage you. The only way they can win is with a Ship's Cannon combo or getting Bloodsail Flybooter randomly generated. I don't understand why anyone is still playing this deck; it's awful. Edit: there's a new version of this that can be quiet scary if they get going, but your gameplan is the same. 
- Priest: Just mulligan for aggro and stay ahead. You're actually faster than them if you survive their swing turns. Illucia doesn't do anything because it costs 3 mana. Control versions play Mutanus and litterally can't win against you if you play around it. If you feel like they're searching for something discover a Wandering Monster, Pressure Plate or Freezing Trap just to be safe.
- The Mirror: Find Rapid Fire before your opponent. Aside from that, you can either go a) speedrun part 2 of your Quest and finish part 3 to seal the deal; or B: find the sidequest and spam your broken hero power to simply burn them down. Do not leave anything alive if you didn't complete the sidequest on the same turn. Shoot your own units. Also, I don't know what idiot told people to keep Flare in this match-up, but simply don't. 
- Demon Hunter: An aggro match-up, but they're slower than you after turn 2. Don't let them snowball and be very afraid on turn 1-2, so much that you sometimes don't play quest. This is because Mana Burn can complete fuck you over if you aren't careful. The deathrattle version mostly can't do anything to you, so just ignore their board and kill them. 
- Druid: Mulligan for aggro and pray they don't get turn 1 Embiggen into full Pirate board (which you beat most of the time btw). The Celestial Alignment version kinda just autowins against you; try to speedrun Quest and pray they draw insanely poorly. 
- Paladin: Don't get Oh My Yogg'ed on some crucial card like Rapid Fire or Quest. An interesting deck with Carnival Clown and Rebuke has been popping up. A really really scary match-up that I think is almost un-winnable if the Paladin plays and draws decently. Remember, damaging divine shields doesn't grant you quest progress. 
- Mage: Mulligan for cheap damage spells that can also go face. Free win if you can find Flare for their Ice Block. Play around Counterspell if it's a secret mage. Some versions use Sorcerer's Apprentice and Sanctum Chandler. If you are far from killing them, generate a Pressure Plate in those scenarioes. 
- Rogue: Generate Snipe and/or search for Flare before they otk you. 
- Shaman: Search for secrets to counter either big Shaman or Doomhammer. Play around Revolve, Devolve or Similar when completing Sidequest.

Substitutions:
This version uses Mystery Winner (for flexibilty), but you can see what works best for you.

Lock and Load
Hunter's Mark
Banana Buffoon
Professor Slate

Damage Table:
Start of round: 0 mana, 3 damage
The Coin: gain 1 mana, 3 damage

- Kill Command (no beast): 3 mana, 6 damage
- Kill Command (with beast): 3 mana, 8 damage
- On the Hunt/Wound Prey: 1 mana, 4 damage

- Aimed Shot: 3 mana, 8 damage
- 2x Rapid Fire: 2 mana, 8 damage
- Arcane Shot: 1 mana, 5 damage

- Powershot (on Leper Gnome): 3 mana, 9 damage
- 2x Rapid Fire (on Leper Gnome): 2 mana, 10 damage
- On the Hunt/Wound Prey (on Leper Gnome): 1 mana, 5 damage