Legendary Artifact Vexing Puzzlebox Whenever you roll one or more dice, put a number of charge counters on this artifact equal to the result
The most valuable one also ranks as the final card from the best-ever Goblin-themed Secret Lair Drop, the aptly named Gobblin & Squabblin
I think that plus the scry gives enough added utility to bump this out of D range, but am ready to be wrong
Incredibly flexible and no mana cost to activate, Astral Slide lets you remove blockers for you and your opponents, stops attackers from hitting you, and of course, lets you blink your own creatures to re-use their ETB triggers and grant them pseudo-vigilance
Foretell makes the card immune to discard effects, so you pretty much have to counter it or win the game by turn six
When a player has 10 or more poison counters, that player loses the game