Hearthpwn

This one was a lot of fun to play. Took a few tries, but I beat the Lich King with it.

The idea is to bombard him with your strongest cards in your collection as early in the match as possible. I've accomplished this by being able to mulligan for Wild Growth and Astral Communion/Naga Sea Witch + Innervate. If you can have Astral Communion + Innervate by turn 3, you've basically already won. The alternative is to play Naga Sea Witch, which, if you can keep it alive (thank you Hozen Healer), you can dominate the same way. If you can play Astral Communion right after Naga Sea Witch, you can play 2 of your strongest minions each turn, which will be really devastating and lead to an even quicker victory.

All the cards I've included are just my best and most relevant picks from my collection. Marin the Fox's treasure gives you a +10/+10 for a minion, which is super helpful for dominating quickly. Reno Jackson is for longevity of course. Faceless Manipulator for pulling off a duplicate of one of your crazy strong minions (likely a legendary). Nourish can be helpful after you've cleared your hand from Astral Communion or for avoiding the need to use Astral Communion entirely by using Nourish before/after summoning Naga Sea Witch (that's how I won).

Let me know if you try this and if you win. Enjoy!