The format only uses cards from the sets released in the last few years, and once a year, the oldest sets are rotated out to make way for the new
Estrid, the Masked Estrid, the Masked requires a very specific deck to work, and its not that powerful even then
There was just a get a ton of creatures into your graveyard deck in the Top 8 of the Pro Tour
It even has some cute interactions with Deaths Shadow and Lurrus, since you are able to loop the card by casting it every end step with Lurrus, and flashing Dress Down in after attacking with Deaths Shadow can give you lethal out of nowhere
Granted, blue decks that splash other colors can have outs to this, but still, protection is nothing to scoff at - Remember that this means blue creatures can't block it, too
Since then, not only have Core Sets been home to reprints that could determine the face of Standard for as long as they were legal, like Mana Leak or Lightning Bolt, but they also had shiny new cards for players to get excited about
