32 cards where the cards aren’t reprints and the mana cost is greater than or equal to {6}{B}{B}

In Garruk's Wake (Magic 2015 #100)
Rise of the Dark Realms (Magic 2014 #111)
Decree of Pain (Scourge #64)
Archon of Cruelty (Modern Horizons 2 #75)
Blood for the Blood God! (Warhammer 40,000 Commander #108)
Archfiend of Despair (Battlebond #44)
Shadow of Mortality (Streets of New Capenna #94)
Avatar of Woe (Prophecy #56)
Bringer of the Last Gift (The Lost Caverns of Ixalan #94)
Valgavoth, Terror Eater (Duskmourn: House of Horror #120)
Plague Wind (Prophecy #74)
Funeral Room // Awakening Hall (Duskmourn: House of Horror #100)
Profane Transfusion (Commander Legends #145)
Void Beckoner (Ikoria: Lair of Behemoths #104)
The Cauldron of Eternity (Throne of Eldraine #82)
Heartless Conscription (Outlaws of Thunder Junction Commander #21)
Gorex, the Tombshell (Midnight Hunt Commander #20)
Skull Storm (Commander 2018 #18)
Torgaar, Famine Incarnate (Dominaria #108)
Dread Cacodemon (Commander 2011 #79)
Bringer of the Black Dawn (Fifth Dawn #43)
Overwhelming Forces (Portal Three Kingdoms #79)
Demon of Death's Gate (Magic 2011 #92)
Kuro, Pitlord (Champions of Kamigawa #123)
Spirit of the Night (Mirage #146)
Hypnox (Torment #64)
Necropolis Fiend (Khans of Tarkir #82)
Iname as One (Saviors of Kamigawa #151)
Tombstalker (Future Sight #91)
Sanguine Praetor (Guildpact #60)
Infernal Spawn of Evil (Unglued #33)
Infernal Spawn of Infernal Spawn of Evil (Unhinged #57)

Though this query has ended, its relics still slumber in New Argive.