So today we have the first of a new class of extinction - an entire converted mana cost!

Several of the rarer CMCs have already fallen - but until now, the “core” 0 to 8 CMCs were all still represented. But no longer!

7-drops

With the loss of Elesh Norn, Grand Cenobite today, there are no remaining cards in the Magic Bracket with a CMC of 7. You can see when some of the other more unusual mana costs fell down here.

New Phyrexia

Elesh was also the last remaining card from New Phyrexia (and the last Praetor besides).

Conflux

Meanwhile, the loss of Path to Exile today means that Conflux is now extinct.