It will refer to the already existing Pokmon TCG Sword & Shield.
Many sites round that to 6.4 x 8.9 cm, which is fine for general reference
More commonly, you see Overlord of the Balemurk in Pioneers Mardu Greasefang, which does a rather stellar job of throwing key cards such as Parhelion II and Skysovereign, Consul Flagship into the graveyard that can re-enter play with Greasefang, Okiba Bosss trigger at the beginning of combat

Shrouding Dark Mist (Legacy of the Duelist) Main Deck Monster Cards Effect Monsters Caligo Claw Crow x3 Giant Germ x3 Mecha Bunny x3 Nimble Momonga x3 Quillbolt Hedgehog x3 Tuner monsters Krebons x3 Plaguespreader Zombie x3 Spell Cards Double Summon Gold Sarcophagus Swords of Revealing Light x3 Trap Cards Call of the Haunted x3 Counterforce Limit Reverse x3 Mirror Force x2 Waboku Xyz Effect x2 Xyz Reborn x2 Extra Deck Xyz Monsters Number 96: Dark Mist x3 Shrouding Dark Mist (Link Evolution) Main Deck Monster Cards Effect Monsters Caligo Claw Crow x3 Giant Germ x3 Mecha Bunny x3 Nimble Momonga x3 Quillbolt Hedgehog x3 Tuner monsters Cherry Inmato x3 Krebons x3 Plaguespreader Zombie x3 Spell Cards Double Summon Gold Sarcophagus Soul Charge Trap Cards Call of the Haunted x3 Counterforce Limit Reverse x3 Mirror Force x2 Xyz Effect x2 Xyz Reborn x2 Extra Deck Xyz Monsters Number 96: Dark Mist x3 Thunderous Dark Storm[edit] This deck is based on Number 96's Duel against Yuma Tsukumo

Experimentation is also key, since it is the only way you will learn what works and what doesn't, and more importantly what fits your playstyle
So far, Wizards has been sluggish when it comes to reprinting mechanically unique Universes Beyond cards in Universes Within form