Hearthpwn

as the question says

Fire Fly
Tar Creeper
Spellbreaker
Fungalmancer
Argent Squire
Glacial Shard
Acherus Veteran
Dire Mole
Loot Hoarder
Acolyte of Pain
Ironbeak Owl (for odd decks)
Cobalt Scalebane
Saronite Chain Gang
Knife Juggler
Stonehill Defender
Doomsayer
Faceless Manipulator
Mossy Horror
Mountain Giant
Primordial Drake
Voodoo Doll (for control mage and warlock)
Arcane Tyrant
Sea Giant

stolen from this thread

Since the list would be very long, i suggest you to watch decklists of the tier 1-2 decks

There you can see the most common cards in each rarity

The above list (in the 1st answer) is just the Neutral ones (and a lot of cards are missing)

• Void Ripper , Crystallizer - Aggressive odd decks
• Gluttonous Ooze 
• Blood Knight
• Corpsetaker - Even Paladin/Warlock  
• Bright-Eyed Scout - BSM
• Carnivorous Cube - Cube decks
• Big Game Hunter
• Skulking Geist
• Corridor Creeper - Odd paladin, Evolve Shaman
• Crowd Roaster - Dragon decks 
• Charged Devilsaur - Recruit Hunter

 

Quote from C_A_W >>

• Void Ripper , Crystallizer - Aggressive odd decks
• Gluttonous Ooze 
• Blood Knight
• Corpsetaker - Even Paladin/Warlock  
• Bright-Eyed Scout - BSM
• Carnivorous Cube - Cube decks
• Big Game Hunter
• Skulking Geist
• Corridor Creeper - Odd paladin, Evolve Shaman
• Crowd Roaster - Dragon decks 
• Charged Devilsaur - Recruit Hunter

 Again, just neutrals. Class cards are easier to see in decklists

 

Warrior :

• Town Crier - Rush
• **Shield Slam 
• Dead Man's Hand - DMH Control Warrior
• Smolderthorn Lancer - Dragon, Odd Dragon
• **Reckless Flurry
• **Brawl
• **Supercollider 

Warlock :

• Gnomeferatu - Control, Cubelock, Even lock 
• Bloodbloom - Mecha'thun
• Treachery - Howlfiend 
• Cataclysm - Mecha'thun
• Twisting Nether - Control, Cubelock
• **Voidlord 

Shaman :

• Unstable Evolution - Evolve 
• Far Sight - Control
• Earth Elemental ,Snowfury Giant - Overload
• Doomhammer

Rogue :

• **Preparation 
• Fal'dorei Strider - Miracle, Tempo
• Evasion - Malygos
• Necrium Vial - Deathrattle
• Vilespine Slayer 
• Academic Espionage - Tess 
• Spectral Cutlass - Tess

Priest :

• **Shadow Visions
• **Twilight Acolyte - Dragon
• Vivid Nightmare - Topsy
• Reckless Experimenter - Deathrattle
• **Cabal Shadow Priest - Control, Dragon
• **Psychic Scream 
• Obsidian Statue - Clone

Paladin : 

• Immortal Prelate - Egg Cube 
• Prismatic Lens - Shirvallah OTK
• **Call to Arms - OTK
• **Avenging Wrath - Even

Mage :

• Primordial Glyph - Tempo
• Book of Specters - Elemental
• Arcane Keysmith - Tempo, BSM
• **Dragon's Fury, **Meteor, **Astromancer - BSM

Hunter :

• **Snake Trap
• Rat Trap - Secret 
• **Master's Call 
• To My Side! - Spell 
• Crushing Walls - Spell

Druid :

• **Branching Paths
• Dreampetal Florist - Malygos 
• **Ultimate Infestation

** - Must haves

 

Thanks guys