While associating existential dread with a childrens game might seem odd, Pokmon has a long history of making its lore dark and disturbing
Slime Against Humanity offers a slow but powerful Ooze token generation strategy using cards in the graveyard or exile
Kiki-Jiki, Mirror Breaker Coming in at #3 is Kiki-Jiki, Mirror Breaker, a card that has broken Modern and other formats with its enablement of various combos that tend to result in a near-endless glut of identical creatures that untap or blink a creature upon entry to the battlefield
If all Farewell were was a mono-colored Merciless Eviction, then it would hit #3 on my list and the nasty Jin would be my #2 card
This was confirmed in a blog post on the official Pokmon site, where it was also revealed that "reprints of popular cards from recent expansions that feature all-new artwork" will be included as well
For better or worse, its unlikely that your copies of Watchful Radstag will double every single turn