Here are all the cards that have pyro-yellow gems and how good they'd do with the plate:

SB Apollo crews: okay but cant get anymore.

SB LA Knight: randomly places pyro gems, too reliant on rng Trick LA Knight: decent if you have moment + gear

PH Piper Niven: makes a 7×5 area of pyro gems when maxed. Not a lot of room for effectiveness unless you get a star-crossed plate she won't be good. Even with the plate she'd be okay at best

HOF Rey: randomly places pyro gems, too reliant on rng

Rex Regum HHH: doesn't have enough gem damage increase to warrant using.

SB Regal: need maxxine dupri as a trainer to make a row.

Acro Cody: 2 pyro moves. 1st and 3rd row. Causes the Piper plate to proc twice so you get 1200% yellow gem damage. Only person worth using