The other option is giving your opponents mean cards to disrupt their game plan or cause them to lose
Do original set foils fit the criteria that I laid out above for why Reserved List cards are valuable
Gamechangers for a Sauron deck The Ur Dragon The Ur Dragon offers a simple strategy, but it's still powerful enough to stampede casual commander tables (and steal a few more competitive wins, too)
Then the second is when Kibo swings, to force the attacked player to sacrifice an artifact
Bloomburrow Spoilers July 17 | Bat Pridemate, Stealing Hand Attack and Classes
In Mary Jane & Black Cat , this interacts negatively with Black Cat's powers to cause bad luck to her enemies, because Felicia still subconsciously sees Mary Jane as a rival and thus causes her to keep getting useless rolls until she manages to work through her issues