Basic

Mind Control: Change mana cost from 10 to 9

Bloodlust: Change mana cost from 5 to 4, minions cannot attack face this turn

Swipe: Only affects minions

Charge: Change mana cost from 3 to 2, Give a minion +2 attack and it can pass through taunt this turn only instead of getting charge

Drain Life: Change mana cost from 3 to 2

Savage Roar: Give your friendly characters +2 attack this turn only against minions

Backstab: Change mana cost from 0 to 1, deal 3 damage to instead of 2

Hunter's mark: Change mana cost from 0 to 1

Innervate: Change mana cost from 0 to 1, Refill 3 empty mana crystals or gain 2 mana crystals this turn only.

Moonfire: Change mana cost from 0 to 1, deals 1 damage to a minion twice.

Sacrificial Pact: Change mana cost from 0 to 1

Totemic Might: Change mana cost from 0 to 1, give +3 health for your totems

Classic:

Mountain Giant: cost 1 less for each minion in your hand

Alexstraza: Set health to 20

King Krush: Change mana cost from 9 to 8

Lord Jaraxxus: Change mana cost from 9 to 10

Tirion Fordring: Change mana cost from 8 to 10

Ancient of Lore: Draw only 1 card instead of 2

Prophet Velen: New text: Battlecry: Your hero power heals or deals damage twice the amount that it would normally.

Holy Fire: Change mana cost from 6 to 5

Faceless Manipulator: Choose a minion and become a copy of it at the end of your turn.

Mass dispel: Silence all enemy minions then deal 1 damage to them.

Mind Games: Change mana cost from 4 to 5, Put a random minion from your opponents deck into the battlefield

Master of disguise: Gain stealth at the end of your turn

Divine Favor: Draw as many cards as many you drew last turn.

Shadowform: Change mana cost from 3 to 2.

Big Game Hunter: Change mana cost from 3 to 5.

Blade flurry: Doesnt deal damage to face.

Equality: Change mana cost from 2 to 3.

Knife Juggler: Juggle can hit friendly targets too

Lightwell: restores health at the end of the turn

Sorcerer's apprentice: after reduction, Spells cannot cost 0 mana

Power Overwhelming: There's an 50% chance that your minion will hit another enemy target instead. (per stack of PO)

Abusive Sergeant: Gives only +1 attack.

Leper Gnome: Deal 1 damage only with deathrattle

Circle of Healing: Change mana cost from 0 to 1

Preparation: Change mana cost from 0 to 1

Shadowstep: Change mana cost from 0 to 1

Curse of Naxxramas:

Void Caller: Change mana cost from 4 to 5

Stoneskin Gargoyle: Change attack from 1 to 2

Mad Scientist: Change mana cost from 2 to 3

Nerubian egg: Deathrattle: summon 4/3

Goblins vs. Gnomes:

Mal'Ganis: Change mana cost from 9 to 10

Dr. Boom: Boom bots deathrattle can hit friendly characters too. (this is how goblin engineering works tho)

Recycle: Change mana cost from 6 to 5

Piloted Shredder: Change health from 3 to 2

Coghammer: Change mana cost from 3 to 4

Muster for Battle: Equip the weapon at the end of your turn.

Call pet: Cannot cost 0 mana

unstable Portal: Cannot cost 0 mana

Mechwarper: Change cost from 2 to 3 mana.

Blackrock Mountains:

Emperor Thaurissan: Change stat line from 5/5 to 6/6, Mana cost reduction applied at the start of your turns.

Flamewaker: Change mana cost from 3 to 4, Change health from 4 to 5

The Grand Tournament:

Mysterious Challenger: Change cost from 6 to 7 mana.

Spawn of Shadows: Inspire: Deal 1 damage to other minions

Poisoned Dagger: 4 durability instead of 3

League of Explorers:

Anyfin Can Happen: Change mana cost from 10 to 9, Summon the murlocs at the end of your turn

Excavated Evil: Change mana cost from 5 to 4

Keeper of Uldaman: Change mana cost from 4 to 5, change attack from 3 to 4