Theres no news about seeing this treatment in a later set or in a Secret Lair tie-in, and the name cosmium is thematically tied to the plane of Ixalan, so I doubt itll be used again outside of a direct tie-in the Ixalan
Meanwhile, your own deck will be filled with counter cards that Atraxa makes many times better
For two mana, this white instant can either prevent all combat damage, regenerate target creature, or counter a spell that is targeting you
However, in Anti-Venom, it's only an upside, as by enchanting Anti-Venom, you guarantee it takes damage, growing it even quicker than normal
Create twice X 1/1 black and green Pest creature tokens with "When this token dies, you gain 1 life." Sorcery Color tag templates(None) Ral's Reinforcements Create two 1/1 blue and red Elemental creature tokens
Whether her spear will be enough to go up against Ursula's claimed trident remains to be seen, but it's a start