Whenever it attacks, the defending player must mill half their library rounded down
When synthesizing this list, I was looking at cards that are asymmetrical in their effect, hard to interact with, or have little ways to remove or stop them
If blue's opponents have more to drink than it does, it follows that its opponents minds will be relatively weaker and easier to manipulate
Cayth, Famed Mechanist Populate and proliferate are both very popular mechanics, and Cayth, Famed Mechanist gives you your choice of which you'd like to lean into more
But Leeches-the-MTG-card removes poison counters (and damages the person that the poison is removed from) which is such a niche alternate-win condition at the time that this is printed
Each of those tokens will enter the battlefield simultaneously