Even after entering a whole new generation, Sword & Shield still holds up as one of the best eras for Pokemon card collectors
Minamo Scrollkeeper, Trusted Advisor, Doctor Octopus, Master Planner, Cecily, Haunted Mage/Eleven, the Mage, and Twenty-Toed Toad each increase your maximum hand size to a specific amount and might fit your deck's plan
It could originally be found as the second version of Duel Terminal (Normal) Parallel Rares, in the sets from May 29, 2011 to February 1, 2013: DT05(a)
It becomes Somehow, I can't say it's brainwashing after errata, but I feel like it's not too close to it, but it's not far from it
I prefer to play Mage Knight solo, and I will play it with up to two other people, but you'll have to set aside most of a day if you want to play this with a full player count