Hearthpwn

This is a pretty fun deck that I crafted using the Khadgar/Galaxy Archetype, I've had a 67% W/R with it so far in Rank 5+

Proofs (Losses include testing stage):

Mulligan

If you get Galaxy, always keep it!

VS Aggro: Magic Trick, Ray of Frost, Mirror Image, Frost Nova, Arcane Intellect

The style of play is to delay the game as much as necessary with freezes/mirror image until you start getting bigger minions. Even if you don't get Galaxy, you will usually end up getting a Zilliax/Mosh'Ogg/Mountain Giant and can handle aggro. It's a harder match up, but unless all the stars align in his favor, you should be fine.

VS Control: Magic Trick, Arcane Intellect, Book of Specters (Only if I have Galaxy), Stargazer Luna

This deck is meant to be played more control than aggro, and if you play smart you should win vs most control decks. Draw as much as you can until you get some kind of combo and unleash it.

 

Types of Combos:

Khadgar/Mountain Giant- Self explanatory unless you've been living under a rock the expansion.

Frost Nova/Doomsayer- Probably the strongest board clear this deck has to offer, and at 5 mana it's extremely useful against pesky Mech Hunters/Aggro Shamans/Rogues

After Galaxy Combos

Archmage + Book of Specters/Arcane Intellect- You get a ton of value, and works as a great way to fill your hand almost immediately with strong 1 drops.

Stargazer Luna- I usually save my Stargazer until after I play Galaxy. It's extremely satisfying playing a bunch of low mana spells and 1 mana minions and having a giant board and a full hand at the end of my turn.

 

Card Choices (Cards that can be replaced/irreplaceable)

There's a lot of flexibility with this deck, I didn't craft anything new for this deck, so you can alternate the big minions with minions that you favor/have. 

Cards with no replacement

Ray of Frost/Mirror Image/Frost Nova - Saves you vs Aggro and makes early game easier.

Doomsayer- Having big spells besides Luna's defeats the purpose of the deck. So yeah you could throw in a Flamestrike or a Blizzard, but 85% of the time, the enemy won't have an answer to a Doomsayer + Frost Nova combo. If you're playing Blizzard or Flamestrike on turn 6/7, chances are you already lost.

Khadgar/Mountain Giant/Conjurer's Calling - Backup plan in case Luna's in the bottom of the deck.

Stargazer Luna- No card compares to this, especially after you play Luna's you can draw 3-6 cards per turn.

Luna's Pocket Galaxy - If this isn't in the deck, you're better off playing Cyclone Mage

Zilliax - It's a staple in many decks for a reason. If you stick it on the board it usually forces a spell or two, or if you attack it head on you restore 6 health. There's always the option of getting a mech due to Conjurer's Calling and hitting something for 10+ dmg and resetting your health.

 

The rest of the deck is pretty flexible, depending on what you have. Here's a few of my personal choices:

Personal Choices:

Magic Trick - Helps you generate value early, and it helps you generate cards to combat whatever you're playing against. A well placed Spellbender is always useful vs Shield Slams on Mountain Giants and Cinderstorm and Arcane Explosion aids vs Aggro.

Arcane Keysmith - Same reason for Magic Trick but a 2/2 on board and a secret.

Book of Specters - You need to use this card wisely. If you end up drawing most of your important spells, this card will usually help you escalate your lead. But if you didn't draw any of your Conjurer's Calling or Galaxy, don't touch it.

Whelp/Cairne- Whelp synergies well with Zillax and the deathrattles help recover from a potential Brawl.

Mosh'Ogg Enforcer- Helps against aggro decks, and classes without single target board clear. 

Burly Shovelfist- Won and saved me more games than I can count. Helps deal with taunts on the board since this deck doesn't have incredible board clear (besides the swarm of minions)

Big Bad Archmage- Synergies well with Khadgar, I may craft another one and add it to the deck.