SCV: 1 mana 1/100: Choose 1, Offense, Defense, Upgrades, Repair
can’t attack, Elusive
Offense: choose 1: Barrack, Stargate, Siege Factory
Barrack 0/4: 2 Mana: choose a Marine,Firebat,Ghost or Medic to add to your hand
Siege Factory 0/5: 3 mana: choose a Tank,Goliath or Vulture to add to your hand
Stargate 0/7: 4 mana: choose a Wraith, Battlecruiser,Science Vessel or a Drop Ship to add to your hand
Defense: Bunker,Missile Turret, Scanner
Build a Bunker,Missile Turret or a Combat Station
Bunker 0/2: take dmg in place of adjacent minions(Marines,Firebats,Ghost,Medic only)
Missile Turret 0/4: can’t attack, whenever an enemy play a minion deal 1 dmg to it
Combat Station 0/7: 2 mana reveal 2 cards in your opponent hand
Upgrades: Engineering Bay, Academy, Armory
Engineering Bay:
2 mana: upgrade your Marines,Ghosts and Firebat attack by 1(max of 3 upgrades)
2 mana: upgrade your Marines,Ghosts and Firebat health by 1(max of 3 upgrades)
Academy:
4 mana:: upgrade your Marines and Firebat so that they can cleave their targets
4 mana: your medics now restore health to all friendly characters and heal for 3 more
Armory
3 mana: upgrade your Tanks,Goliath and Vulture attacks by 1(max of 3 upgrades)
3 mana: upgrade your Tanks,Goliath and Vulture Health by 1(max of 3 upgrades)
Repair a mech(+2 health), upgrade a Mech +1 max health…each turn choose 1
(Repair doesn’t cost mana but can only be use once per turn)
Marine: 2 mana 2/3: battlecry deal 2 damage to a minion, if the target is a Zerg or a Beast replay this battlecry
Firebat: 3 mana 3/2: End of Turn deal 5 dmg split among random targets
Medic 2 mana 1/6: End of turn restore 3 health to the most damaged friendly character(prioritize minions), Elusive
Ghost: 4 mana 5/3 :battlecry: deal 3 damage to 2 targets of your choice, gain stealth if it kill both
Vulture: 5 mana 4/4 Battlecry: summon 2 mines on your opponent battlefield
Mine: when you play a minion this explode for 4 damage(only 1 mine trigger at a time)
Goliath: 7 mana 6/5 shoot 8 missiles at random targets that deal 2 damage each(maximum of 4 shots will hit the enemy hero)
Siege Tank: 6 mana 6/6: Battlecry: Choose Siege mode or non-siege
Siege: can’t attack, once per turn you can choose a target to deal 7 damage to
Non-Siege: Rush, take 3 less dmg from attacks
Drop Ship: 8 Mana 1/4: Battlecry: choose units to fill this ship(can be fill up to 8 slots),
Rush, Deathrattle: summon the units inside it(battlecries units trigger their battlecry when summoned but at half the power)
1 slot units(Marine,Medic)
2 slots units(Firebats,Ghosts, Vultures)
4 slots units(Siege Tank,Goliaths)
Wraith: 7 Mana 4/3: once per turn choose a target and deal 3 damage to it, if it kill it gain stealth, Battlecry: summon 3 copies of this
Science Vessel: 8 Mana: Elusive, End of Turn: deal 5 damage to all enemies
Battlecruiser: 10 mana 6/16: Battlecry: choose a target: then choose to deal 8 damage to them this turn OR Charge up and deal 20 dmg to them at the start of your next turn
Jim Raynor(Marine Suit) 2 mana 2/3 Legendary: battlecry: deal 1 dmg 3 time to a target of your choice
Jim Raynor(Vulture) 4 mana 3/6 Legendary: Rush, whenever this kill a target it may attack again, end of turn: summon a mine on your opponent field
Sarah Kerrigan(Ghost) 4 mana 5/4 Legendary: Stealth, this turn and at the start of each next turn choose a target to deal 3 damage to, this remain stealthed as long it doesn’t directly attack
i had to after the announcement of Starcraft coming to HS 
not gonna do the whole of Protoss and Zerg though XD
but throwing my favorite Starcraft hero in
Zeratul: 5 mana 7/2/3: Stealth, Battlecry: destroy 2 random minions, whenever this attack and kill a minion regain stealth, End of Turn gain +2 Psyonic Shield energy
7 = attack
2 = health
3 = Psyonic Shield(energy barrier)
EDIT: fixed Zeratul so that he fit more accuretly his Starcraft design
EDIT 2: added the SCV unit :)…that 1 was so much writing 
EDIT 3: slightly nerf the Goliath idea, a bit too strong after consideration…it now has a cap of 4 hits on the enemy face
EDIT 4: lil tweak to drop ship so that some units dont come down as dead, also added Vulture as a 2 slots unit(forgot to put it there last night)…yes i know that Goliaths are normally 2 slots but i put it as 4 slots so that it is more balanced