Aside from Dredge, which became a multiformat boogeyman that shaped tournament play for a decade (and even then, I would argue Dredge was a positive development for the game's legacy), there's little to quibble about Ravnica: City of Guilds
Officially, there are only 39 copies of this card in the world
All of these will trigger the Aethermage, and you can tap a mana to draw a card when they do
There are a lot of ways for things to go horribly wrong, but even more ways for things to go Hollowly right
what we were releasing hadn't grown at all
This promo can be found in a variety of conditions across the spectrum, with damaged copies selling for as low as $12.99, with heavily played (HP) cards selling for about the same amount