Shadowverse

For example, remember the Druid Beast with the girl from Karazhan, who summoned a copy of the beast.

Oh, by the way, yes, I remember my friend managed to get a Legendary card with this deck in the first three days of Karazhan, and then it started losing to everyone.

And there were no other Warlocks besides the Zoo Warlock.

The old Malylock was fun, with the Dark Bomb. I didn't manage to build it back then either. Later, in the Karazhan meta, I played a fun Malylock, but it was more like a Dragonlock with an alternative way to finish the game through Maligos and Soulfire. And also an OTK with the old Arcane Golems, but that was also more of a fun deck.
The new Handlock, by the way, doesn't seem like a very strong deck to me, but it's definitely worth paying attention to. The new 4/8 "cannot attack" minion fits perfectly into the deck. Against Pirate Rogue, turn 2 Doomseer - turn 3 is amazing - turn 4 4/5 Sentinel, and on top of all that, a taunt - the Pirate Rogue gives up. If the taunts don't work, you give up. And the main counter right now seems to be the infamous Quest Mage with its additional Ice Blocks and freezes from various random generators.