Undead deck: 

SKEL KNIGHT: The basic front liner unit of the Undead type cards. Skills:

 — UNDEAD: Stunned attacks do damage instead.

 — SNACK: When this card kills another, gain 2 health.

 — SURVIVER: Will survive any attack if card has health but can no longer attack if health is 0. Can only do it once.

SKELETON: The basic front liner unit of the Undead type cards. Skills:

 — UNDEAD: Stunned attacks do damage instead.

 — EAT: when this card kills another, gain 4 health.

SKEL GUNNER: The high damage range unit of the undead cards. Skills:

— UNDEAD: Stunned attacks do damage instead.

— RELOAD: After every shot, takes a turn to reload. Can only reload on field.

— RECOIL: take 1 damage after each shot.

SKEL PRIEST: Heals other cards with unholy power. Skills:

— UNDEAD: Stunned attacks do damage instead and heal spells hurt.

— DARK HEAL: Heals another undead card for 2 health but if there are no undead cards to heal, try and heal another card that is not undead for 1 health. cost 1 mana.

— MANA GATHER: Ever 2 turns generate 2 mana for player.

SKEL GUNNER: The high damage range unit of the undead cards. Skills:

— UNDEAD: Stunned attacks do damage instead and heal spells hurt.

— WIDE RANGE: Shoots at random enemy's on field. 

— SPELL CASTER: Cast a spell on a random enemy on friendly every 2 turns.

— SPELLS: ZAP 5x 50%, MANA SHIELD 30%, and FIRE BALL 20%.  MANA SHIELD 100% when no enemy's on field. 

Other things I changed:

Goblin: A common monster that fights in groups

 — AMBUSH: if move to front, attack enemy in front for .5x damage.

 — HORDE: if there is no card to attack, attack a card that another goblin is facing dealing .5x damage.

 — RETREAT: if card is about to die, retreat back into backline if there is space, if no space it will die, can only do it once. ( Added )

Increased damage of the FIRE WORM
and some other things I forgot.

I know the game needs a lot of balance changes I will do that at when I have a lot of time on my hands.