Hearthpwn

The plan is to play Spirit of the Frog a soon as possible to draw cards with your cheap spells, play Emperor Thaurissan, survive until you play Malygos and hit face with your spells.

Remember a 0 mana Lightning Bolt can draw a 1 mana Lightning Bolt. This is also how you can win with Malygos and Spirit of the Frog on board hitting face.

The combo is Malygos + 2 x Lightning Bolt + 2 x Totemic Smash = 30 damage, good against most classes.

Warrior/Druid = same as above but you gotta keep Frost Shock + Lava Burst to go over 30 damage or find more burst with Haunting Visions

Eureka! is used to play Malygos sooner if you can't find Emperor Thaurissan combo with 4 cheap spells. 

Bloodmage Thalnos can be used with Malygos for more spell damage. 

Mulligan: Aggro  = Zap! + Lightning Storm + Loot Hoarder                 

               General = Far Sight + Spirit of the Frog + Zap!

Cards not used

1. Alexstrasza There is too much healing now, most of the time it won't matter if you play it. 
2. Jepetto Joybuzz it rely on not drawing Malygos before playing it, not a consistently good strategy.
3. Hagatha's Scheme I never draw it early enough and it's bad against deathrattle/reborn minions.

This is a fun but not easy deck. I've started back to rank 20. Now rank 8 and climbing. I don't know yet if this is Legend reachable but i'll try and update next month.

There's always changes you can make! Just don't add too many minions to make Eureka! weaker.