Hearthpwn

#1 Lyra the Sunshard "Behold the glory of a new sun!" Kreygasm "Illuminate!"

also up there:

Kobold Illusionist "Oooh! Monsters behind you!"

 Mogor the Ogre "Mogor des-uh, no, Mogor destr-uh, wait, no MOGOR KILL!"

Ysera "I dream and the world trembles."

Drakonid Operative "Secret Agent coming through."

Shudderwock "My jaws that bite! My claws that catch!"

Prophet Velen "Not all who wander are lost."

 and i'm sure i'm missing plenty but that's a long enough list :P

Angry Chicken

Tiny Knight of Evil - "Small in size, Huge in Eevilll" and "Here we go"

Also

Shroom Brewer - "bububububu-bubbly"

Stormwind Champion - "For the Alliance!"

My other favorites have already been mentioned. 

Tortollan Shellraiser  Tortolla preserve us

The correct answer is always Feral Gibberer. It's not possible to hear its play, attack and death sounds and not at least get a smile out of it.

Honorable mention to Cabal Shadow Priest, Let Me Change Your Mind. Great voice line, love getting value off of her, and is one of the coolest golden effects in the game.

Millhouse Manastorm’s coughing when he dies. So much drama, I love it! 

Easy question :-)))

Oooh! Monsters behind you!

Taz’dingo! Yehehes

And the music of blackhowl gunspire music is also very awesome

You will beg for mercy... and I will deny you!

 Bolvar, Fireblood - "ANSWER FOR YOUR CRIMES!"

mine is mute on my remote :D

Nemsi the new warlock hero’s voice always make me giggle. “Whoa, too many cards” 

“this guys toast”

best attack is “tah daaaa”

obv : Oh monster behind you " so cute and funny > kolbold illusionst

anything with funnel cake

Obviously Wretched Tiller is the best. The delivery by the voice actor is hilarious.

"Golly bob-howdy, I am undead!"

The hillbilly is genuinely surprised and amused about his (un)life after death. I put him in every joke/meme deck I use against friends.

"Leeeeroooooy JEEEEENKIIIINSSSS"

Quote from MikaelM >>

Obviously Wretched Tiller is the best. The delivery by the voice actor is hilarious.

"Golly bob-howdy, I am undead!"

The hillbilly is genuinely surprised and amused about his (un)life after death. I put him in every joke/meme deck I use against friends.

 Now I finally now what he's saying lol good one

BY FIRE, BE PURGED!!!

"You require my assistance?"
"Aha!"

''By the elements combined'' Kalimos, Primal Lord