The second set, Rise of the Floodborn , arrived a few months ago
As long as Knife and Death is on the stack, players can't cast spells, activate abilities, or move their permanents
Theres also random needles if the dripping gore in the brain hole isnt enough for you
Number 8 Language English Legal Formats Brawl, Commander, Competitive Brawl, Timeless Restricted Formats Vintage Not Legal Formats Alchemy, Modern, Pauper, Pioneer, Standard Banned Formats Historic, Legacy Rulings (6/8/2016) The "shuffle and put the card on top" is a single action
a Mark Rosewater (May 17, 2021)
by restricting the mechanic of playing cards during the opponent's turn to the attack phase, it should be fine to implement in TCGO (you don't need to have players pass priority during their turn, you only need to ask Player B if they want to play something when Player A uses an attack, once per turn)