I have a few of those, but the one I will never abandon if I'm playing Grixis colors is, well, the ultimate thing to do with seven mana
Or when the game state simply no longer favors that permanents strengths a mana dork once youve curved out and emptied your hand or a one-drop that is heavily outgunned in the late-game boardstate
The Mana production was from Burnt Offering, by sacrificing a creature, and Song of the Damned, by adding Black Mana based on the number of creatures in your graveyard, both cost one Black Mana and could be used efficiently to get more Mana from one spell than a Dark Ritual, which was also reprinted in Ice Age
It's also worth noting that trading will eventually be added to the game, so if you don't want Shop Tickets or Flair, maybe consider saving some rarer cards for trades down the road
The exception is in knights decks in EDH, especially Haakon, Stromgald Scourge, which can get you the Knight back when you need it
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