mtg enter the dungeon cards Magic Gathering Trading Card Game Adventures in the Forgotten Realms Single Card Rare Zalto, Fire Giant Duke 171 FOIL puts those cards into their hand Dungeon Delver - Commander Legends:

Chromatic Lantern: one of the best mana rocks for mana fixing, and a key reprint in this product

Its uniqueness, rareness, and power all make for the most valuable card in Edge of Eternities

12 Ursula: Deceiver Of All Card Number 91/204, Emerald Ink Ursula: Deceiver of All is going to be a difficult card to find, as it is listed at the Legendary rarity, yet for those lucky enough to get her, she can be a vicious card in a song-heavy deck

or is it

These need two things to succeed: mana to cast a dozen or more spells, and card advantage to find those spells

I wont include cards that already have unblockable, only cards that grant others unblockable abilities