Ref:
* Alliance - 8% each, Production X2
* Barbarian - 9% each, enemy wall (Common - 3, Uncommon - 8, Rare - 15)
* Brigand - 7% each, steal stock (Common - 1, Uncommon - 2, Rare - 3)
* Beast - 8% each, more attack (Common - 2, Uncommon - 5, Rare - 10)
* Burning - 8% each, discard a card + enemy tower (Common - 1, Uncommon - 3, Rare - 5)
* Dragon - 11% to draw a rare Dragon.
* Holy - 12% each, discard Undead & more stock (Common - 1, Uncommon - 2, Rare - 3)
* Legend - 25% to raise one of facilities (lowest) by one
* Mage - 10% each, return half of gems
* Soldier - 10% each, return half of recruits
* Undead - 10% each, return 1/3 of total cost
* Unliving - 10% each, return half of bricks