My List:
the meta changes every now and then and only with just a single card wouldnt work without its support… im just happy dawngrasp is off my list now and i hope bran gets rotate out soon because with these new powerful cards they can make some crazy thing happen… and yeah i hate druid so much!
Druid : “I don’t think i like you”
HIGH FIVE
Every current Druid card in rotation
Renathal
Guff
Hunter Quest
Mage Skeleton Anything
Thief Anything
denatrius
theotar
trogg
patchwork aka mutanus on steroids
hunter quest
dishonerable mention for tickatus
and to be fair most secrets are obnoxious
Dirty Rat
Theotar
Patchwerk
Mutanus
Objection
burden of pride
jackpot
any other card with that angle of a troll face
I really hate Mana Drain! That’s why I play it in all of my blue decks.
pretty much all of my most hated cards are druid’s mana cheat BS and ofc sire D, THE most feelsbad card of all.
Well, my most “hated” list doesn’t really line up with what cards I think are “problematic”. But probably:
Honorable Mention: Shockspitter (The new 2 drop hunter beast that scales off your hero attacks.)
My most hated card was the mage quest that is all most stuff doesn’t bother me that much.
Convincing infiltrator is definitely up on my list
There’ve been many, hard to remember all of them after all those years (I retired during Un’Goro, returned only for Classic, which I play now).
It’s hard to make a list even from the current Classic set, which I still play, but some notable ones are:
Some other contenders from Wild sets include:
I could go on…
There, I made this a little more honest! 
Denathrius, Shockspitter, Zephris, Brann, Guff
Oh, yeah, also Tunnel Troggs, 4 mana 7-7s and so on… Of course, it’s probably funny compared to modern day’s offenders.
yet the #1 problem is the enabler of all the toxicity… Brann Bronzebeard
you forgot Tikatus and gnomeferatus