Hearthpwn

War Golem and Murloc Raider are the 2 change answers, While wisp, and Murloc Tinyfin are 1 change each. 

Next: 4 cost 5/4 with "Has a fifty percent chance to attack the wrong enemy." (2 changes, 2 answers, keep the randomness please.)

Murloc Knight costs 4 and inspires for a random murloc.

Next: 1 cost 1/1 Deathrattle: Deal 1 damage. ( 1 change, 1 answer)

Do you mean Murloc Raider? Because that is one change, the decrease of health. If you don't ignore the next puzzle.

Next: 6 cost 4/6 with at the start of your turn put a random minion into your hand. (1 change, 1 answer)

Fel Reaver has "Whenever your opponent plays a card discard the top three cards of your library."

Next: 5 cost deal 5 damage to a minion. ( 1 change, 2 answers)

Troggzor is Correct, but the other one was meant to be Hogger, Doom of Elwyn

Mechenginer Thermaplug is the answer to yours.

Next: 0 cost deal 3 damage and draw a card. (2 changes, at least 6 answers)

There are a lot of possibilities. Nefarian fits, all minions with only charge on them fit.

Next: 7 cost 6/6 wheneve this minion takes damage, summon a Burly Rockjaw Trogg. (1 change, 2 answers)

Shadow Word: Horror is 4 mana and only destroys enemy minions.

Next: 3 cost 3/3 Battlecry: deal 2 damage to all enemy minions. (2 changes, 1 answer)

The second one is Twisting Nether, 2 changes in the cost and the removal of "that cost 3 or more."

Anyways King Krush is a beast hunter-exclusive legendary. If you were looking for something else, you should have asked for more answers :P.

Next: Give a friendly minion +2/+2. (1 change, 2 answers.)

Wrath deals 3 damage to only a minion, or 1 damage and draw a card. Shiv does 1 damage and draws a card, and Darkbomb does 3 damage.

Next: 4 cost destroy all minions that cost 3 or more. (2 changes, 2 answers)

Emperor Thaurisan is a 6 cost 5/5 that decreases the cost of cards in your hand by 1. 

Next: 5 cost 2/2 with Deathrattle: Return this card to your hand. (1 change, 1 answer)

Fossilized Devilsaur has taunt if you control a beast, Ironbark Protector has taunt, Anubisath Temple Guard is a 6/15, and Ragnaros The Firelord can't attack and deals 8 damage to a random enemy at the end of your turn.

Next:  4 cost 5/4 Overload 1. (1 change, 2 answers, I want both)

Carine Summons a 4/5 Baine Bloodhoof. Baine only costs 4 to play.

Next: 5 Cost 10/10 Taunt. (1 change, 1 error)

Totemic Might-- Only to your totems

Next: Destroy a minion. Its owner draws to cards. (1 change, a lot of answers)

Toshley. It costs 6, is a 5/7 and has deathrattle add a spare part to your hand as well.

Next: All other characters have a 50% chance to attack the wrong enemy. (2 changes 1 answer)

Mech Yeti correct and I didn't realise that I hadn't said both players, I was meaning it to be "random", which isn't in the card text.

Humility changes the attack to 1 not health, Equality changes all minions health to 1, and Aldor Peacekeeper changes an enemy minions attack to 1.

Next: Deal 5 damage to an enemy, or deal 2 damage to all enemy minions. (1 change, 1 answer)