These creatures are excellent for attacking and blocking with on their own, and the life gain is a nice bonus
A set like Unstable is for casual games and released as fun, non-legal cards
Since the few anti-Poison tech cards are too narrow for most Commander metagames, opponents receiving their first Poison counters face an unappealing choice: either unapologetically gang up to immediately remove the proliferate deck from the game, or dont and then try to act surprised when that player inevitably wins the game a few triggers later
Flash has a similar story
2021, however, finally gave us access to Quirion Ranger in Modern when it was reprinted in Modern Horizons 2
C13 introduced some mechanics specifically built for Commander, like tracking how many times a single commander card has been cast and interesting ways to move commanders out of the command zone