Both require you to pay a cost to get an effect
Nadiers Nightblade Zulaport Cutthroat, but make it token-specific
This means that you can fit split second cards into virtually any deck , either as a backup for a spell that you need, or as an alternative that your opponents can't deal with
MTG Tap/Untap Decks Because all decks tap and untap permanents, building a whole deck based on this keyword action isnt viable
Theres also a shop cat, but sadly, we didnt see her
Awaken the Erstwhile Balancing Act Chandra Ablaze Creeping Dread Cunning Lethemancer Dark Deal Delirium Skeins Dragon Mage Earsplitting Rats Enemy of Enlightenment Fanatic of the Harrowing Flux Gutmorn, Pactbound Servant Ill-Gotten Gains Incendiary Command Jace's Archivist Kardur's Vicious Return Kefka, Court Mage Largepox (playtest) Liliana of the Veil Liliana, Defiant Necromancer Liliana, Waker of the Dead Magus of the Jar Magus of the Wheel Marsh Crocodile Memory Jar Miasmic Mummy Mindlash Sliver Mindslicer Naktamun Lorespinner Neheb, the Worthy Rankle's Prank Rankle, Master of Pranks Reforge the Soul Rix Maadi, Dungeon Palace Rotting Rats Runehorn Hellkite Seek Bolas's Counsel (playtest) Sensation Gorger Serum Raker Sibsig Icebreakers Sire of Insanity Strategy, Schmategy Strongarm Tactics Stronghold Rats Wheel of Fate Wheel of Fortune Whispering Madness Windfall