Force of Negation Easily the most playable of the Force cycle from MH1, Force of Negation is a key card in Modern that is designed to keep things at least somewhat fair
Here are a few: Atarka, World Render might have more of a win-more ability, but double strike on your dragons is a legit wincon
Borderless Web-Slinger Cards This treatment shows alternate versions of Spider-Men, ranging from Peter Parker to Miles Morales, and even the Radioactive Spider that started it all
Securing a land drop and giving you an extra card to play later is exactly what blue-red tempo decks need to keep up the pressure and not die down after some turns
Kaito, Cunning Infiltrator $15.46 Kaito, Cunning Infiltrator is tailor-made for ninja decks, and decks that care about saboteur effects in general
These ones are my personal favorite because it is totally random, and entertaining as hell to open