Legendary Ramp Druid
This is a custom deck I created because I have too many goddamn legendary cards and I wanna play with all of them! It's a ramp druid deck that uses Barnes, which synergizes with a ton of Legendaries like Fandral Staghelm, Cairne Bloodhoof, Sylvanas Windrunner, Aviana, Chromaggus, Ysera, Deathwing, Dragonlord and Y'Shaarj, Rage Unbound.
This deck is almost always fun to play, very small odds of not being fun :)It's easily gotten me to rank 12, the only times I lose are against really aggressive shaman or hunter decks, and that's only if I don't get some early game mana growth.
I usually mulligan for wild growth (duh), innervate (duh), raven idol (duh) or mire keeper, or fandral, or barnes. As you can see, this deck is hard to not have fun with!
Innervate x 2 Raven Idol x 2 Bloodmage Thalnos Wild Growth x 2 Wrath Feral Rage Mulch x 2 Barnes Fandral Staghelm Mire Keeper x 2 Swipe Nourish x 2 Cairne Bloodhoof Emperor Thaurissan Sylvanas Windrunner Chillmaw Chromaggus Aviana Cenarius Soggoth the Slitherer Ysera Deathwing, Dragonlord Y'Shaarj, Rage Unbound Arcane Giant
Here's a Druid ramp deck that I basically copied from [this smart person]. I found this deck to be pretty fun, and I won a lot from ranks 18 - 12ish. This deck is for Hearthstone Season 29, August 2016.
Innervate x 2 Raven Idol x 2 Power of the Wild Wild Growth x 2 Wrath x 2 Feral Rage x 2 Mulch Barnes Fandral Staghelm Swipe x 2 Nourish x 2 Cairne Bloodhoof Emperor Thaurissan Starfire Sylvanas Windrunner Ragnaros the Firelord Aviana Cenarius Ysera Deathwing Deathwing, Dragonlord Yogg-Saron, Hope's End Y'Shaarj, Rage Unbound