Unsurprisingly, Kinnan, Bonder Prodigy sees heavy play in competitively-leaning Commander builds as its able to do so much
For those who aren't interested in milling their opponents, when used to mill yourself, high-toughness creatures in a Phenax deck can easily enable self-mill win conditions like Laboratory Maniac and Thassa's Oracle.
With Siege Rhino in the same $3-$5 range its tough to imagine Tasigur rising above that, but he could easily keep pace with Rhino
Prosper is the poster-boy for Treasure decks, and is actually more of an impulse-draw Commander, but its six of one and half a dozen of the other
All that said, Severina definitely isnt a bad card
Ravensburger hasn't released this kind of information yet, but we'll be sure to update the guide if those details become public