Vote on poll 

I am so glad rotation has come and infinite value is finally gone. 

It's a tough one i hate them all.

Psychic Scream NR 1, Spreading Plague NR 2

Really harbringer celestia? i have one in golden that i never used do to it sucking so badly.

Clearly harbinger celestia is the real op villian here. Move over dks    

Fungalmancer 

Harbringer Celestia has just broke the game for me. Uninstalling Hearthstone.

I miss Voidlord.

Yogg- i lost the game but fuck it I can still win- Saron

Without the poll this question would be actually legit. But I believe you just want someone to support a claim of yours / prove your point. It's such a biased poll, even Celestia can't help you :(. 

Ultimate infestation ?

Wait, WHAT?
Where are Patches the Pirate (pre-nerf), Bloodreaver Gul'dan, Ultimate Infestation, Baku the Mooneater, The Caverns Below (pre-nerfs), Ice Block, Kazakus, Barnes, Naga Sea Witch (pre-nerf), Murloc Warleader (pre-nerf), Raza the Chained (pre-nerf), N'Zoth, Voidlord, Possessed Lackey + Dark Pact (pre-nerf), Eternal Servitude, Jade Idol and Jade Blossom?
The cards in that poll (except for Spreading Plague) haven't been the most toxic ones in the last 2 years.

Rexxar was never really good until we got some beasts with life steal and rush in Witchwood. I voted Plague, because it was probably the biggest contributor to Druid dominating for such a long period. Ultimate Infestation isn't nearly as good without it.

Priest Spellstone, Rexxar, Jaina, Baku, Cube, Play Dead, Togwaggle, Spreading Plague, Branching Paths, Shudderwock, Giggling Inventor, Rogue Quest, Guldan, Level Up!, Hunter Spellstone..........

Take your pick

Shudderwock.

The card is obviously a perverted design, no matter how effective it is.

Toxic top tier: Baku, Genn, Ultimate infestation, Hunter spellstone, Prince turn 2, Shudderwreck, Jaina DK.

Honorable mentions: Psychic scream, Spreading plague, Guldan DK, Cube, Corridor Creeper.

Of those cards listed, most existed and were not "toxic" until other cards were printed to make the archetype work. 

The exception? Spreading Plague.   That one card by itself turned the game into Druidstone by giving druid a solution to its major weakness.  I couldn't believe the card when it was revealed, and thought it should have been nerfed to oblivion instead of by one mana.

However, the are many other cards that should be on that list too, as others pointed out.

Were is guldan, odd/even legendary, skull, doom guard, cube, rogue quest, jade idol (2 years back it was still standard legal) mecha c'thun, mountain giant on t3, voidlord, 2 mana prince,velen.And im sure there is more this is only the ones i could think of.

Cube, off the top my head, and anything which recruits.

Are we going to ignore Divine Favor?

Fucking Dooomguards .