MAybe queen and bishop for the long diagnels
Most important piece in 3 Check

Queens and Rooks are the most powerful pieces for their ability to easily give one or more checks, even from a distance. Knights are also very good though because you can't block a Knight check. Also, unlike Bishops, Knights can use the whole board. For example if you get into an endgame where you have a Knight vs your opponent's Bishop then you have a big advantage as you can just keep your King on the opposite color as the opposing Bishop to avoid checks whereas your opponent will have to constantly move their King to avoid Knight checks.

Queens and Rooks are the most powerful pieces for their ability to easily give one or more checks, even from a distance. Knights are also very good though because you can't block a Knight check. Also, unlike Bishops, Knights can use the whole board. For example if you get into an endgame where you have a Knight vs your opponent's Bishop then you have a big advantage as you can just keep your King on the opposite color as the opposing Bishop to avoid checks whereas your opponent will have to constantly move their King to avoid Knight checks.
I agree
What is the most important piece in 3 check? Is it the bishop, which can deliver unexpected checks? Or the knight? Or the queen? Perhaps even the lowly pawn? I'd like to hear your opinions and experiences!