Things that we want to see in Limited or casual Constructed but usually not in multiples for complexity reasons tend to go into uncommon
Faerie Mastermind leaves the room when this card shows up
Sivriss, Nightmare Speaker supports sacrifice synergies and graveyard shenanigans, milling a card for each opponent upon sacrificing a creature, and then returning that card to your hand unless that player pays three life
I have the pleasure of interacting with nearly every product we create, so I am "uniquely positioned to write an article that goes into detail on all of the Core Set 2021 products" according to the mean product architect who didn't want to write this article himself
Lay down Madam Mim to cycle Merlin cards into your hand and play them again to rack up the points and leave your opponents unable to stop your game-winning combo
If you build your Commander deck right, you probably won't be using that fourth ability very often