Hearthpwn

Hey guys my name is deliciouz and I reached legend with this highlander Mage.

Proof: https://imgur.com/Ucl84sA

I have no stats because I play mainly on my phone. This Deck is decent against most of the common decks in the ladder. The worst match up is against aggro DH.
This Deck is not easy to pilot but a lot of fun. You can win some games only with The Amazing Reno or Puzzle Box of Yogg-Saron.
Sometimes you can just Dragoncaster+Puzzle Box of Yogg-Saron and turn a losing game. 

Mulligan Guide:

vs. Demonhunter: This is the worst match up because they will face rush you. So keep early board removal like Arcane Breath, Frostbolt or Zephrys the Great for early board or removal. Keep the taunt minions and freeze card. You need to stall until you can stabilize the board. 

vs. Galakrond Warlock: I would say this match up is easy. Most of them play slowly. They will Heropower on turn 2 and play Dragonblight Cultist on turn 3. You just need to ping. Try to bait Plague of Flames before you play your big minions. This matchup will mostly end in a late game. So keep The Amazing Reno for their Galakrond, the Wretched.
Be careful most of them runBad Luck Albatross don't clear it if you want to play cards like Reno or Alex next turn.

vs. Druid: There are 2 variants of Druids. Spell and Big Druids. Both of them are really slow. In early game they try to ramp or clear your board. Be careful if they can ramp 2 times in row. Keep early minions.

vs. Hunter: Most of them are Aggro Beast Hunters. Clear their early minions with your hero power or cheap spells. Try to Polymorph cards like Teron Gorefiend orAugmented Porcupine. Keep your taunts and clear the board.

vs. Priest: Easy. Most of them play quest. Just wait until late game don't let him finish the quest. So don't ping his face. Just clear board. Bait Plague of Death before swarming the board. If it's a taunt priest just Polymorph the minion. So they can't resurrect them. Keep early minions.

vs. Mage: I faced only 2 Mages. Both played the Spell only Mages. They are also slow. You will win in late game. Keep early minions. If you face highlander Mage bait their Alex before playing Reno.

Possible Card Changes: 

If you face many DH you can add Acidic Swamp Ooze 

If you face many Galakrond Warlocks you can add Bad Luck Albatross.

You don't need to craft Astromancer Solarian. If you lack some cards Cone of Cold, Doomsayer, Messenger Raven, Flame Ward, Ruststeed Raider are options