66 x 91 card sleeves Solid Color SECURE SUSPENDER Gamegenic: MATTE Standard Card Game

However, they have been completely outclassed by the last 20 years or so of duals and are unlikely to be played anywhere unless you have bonkers counter proliferation throughout your deck

cards are smaller then the standard format used by other TCG like Disney Lorcana , Magic and Pokemon

(6/14/2019) In a Two-Headed Giant game, damage dealt to you and/or your teammate that would reduce your team's life total to less than 1 reduces it to 1 instead, as long as you control a creature

Also, every trap in Crystal Beasts takes up a slot that could be used on face-up Crystal Beast continuous spells, so thats another problem