Each of those, like the Darkness Crystal, will reduce the mana required to cast a spell in its appropriate color by 1, and will cost four mana two of the color of choice, but the rest is unique to each Crystal
To me The List is an excuse to claim something got reprinted while in reality nobody knows exactly how rare a find the cards actually are
In black and green, the options for creature recursion and sacrifice outlets are numerous, so consider Gravecrawler or Reassembling Skeleton, or cards that are already mutants (and believe me, we expect more) and think of them as draw two cards when they die
Etali, Primal Storm If you're playing dinosaurs in Commander (and sometimes even if you're simply in red), Etali, Primal Storm is a card you'll no doubt want in your deck
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Whenever a permanent phases out, it is no longer affected by anything going on in the game
