The ideal scenario is having at least two good dredgers in the graveyard (Imp and Thug counts, Darkblast should be counted as a support card) before casting Reunion
The rad counters can trigger the milling, but youre obviously going to want to include a lot of other ways to mill in your deck
I like this effect so much Im also running Sword of War and Peace for the protection, lifegain, and burn effect
These decks would thrive off the combo of Vein Ripper and Sorin, Imperious Bloodlord
Instant Color tag templates(None) Thought Scour Target player mills two cards
Why its a contender: Crucially, it allows players to stop game-winning threats even when they have no available mana, fundamentally changing how high-power formats are played