In my life I’ve seen interesting discussions about which JRPGs have the best protagonists and which ones have the best non-protagonist party members but I don’t think I’ve seen this one.
Since “best” can mean anything subjective let us know what it means in your case! i.e some might choose a party based on the writing+design of the characters, others might focus on their character arcs and themes, or on the overall diversity of the party (full human teens party vs diverse ages or diverse species vs whatever Chrono Cross has going on, etc).
I love the cast of Persona 4.
They really nailed that feeling of a group of friends out to solve a mystery. Even better if you played the Golden version of the game.
While I love 3 more as a whole story-wise I feel like 4 developed the bonds of the supporting cast much better and showed how they all cared for each other.
All the events and trips you could go on with each character really developed them out nicely and it was great helping them overcome their personal issues and grow stronger as a person (and in battle thanks to the perks and advanced personas).