Here’s a large cross-platform list of RPGs where the active party size is greater than 4
Baldur's Gate — up to 6 characters Baldur's Gate II: Shadows of Amn Icewind Dale Icewind Dale II Planescape: Torment Pillars of Eternity Pillars of Eternity II: Deadfire Pathfinder: Kingmaker Pathfinder: Wrath of the Righteous Tyranny Temple of Elemental Evil Solasta: Crown of the Magister Arcanum: Of Steamworks and Magick Obscura Wasteland 2 Wasteland 3 Expeditions: Rome Expeditions: Viking Black Geyser: Couriers of Darkness Suikoden Suikoden II Suikoden III Suikoden IV Suikoden V Eiyuden Chronicle: Hundred Heroes Chrono Cross Final Fantasy IV Final Fantasy VI Final Fantasy Tactics Tactics Ogre: Let Us Cling Together Tactics Ogre: Reborn Ogre Battle: March of the Black Queen Ogre Battle 64: Person of Lordly Caliber Radiata Stories The Last Remnant Dragon Quest IV Dragon Quest V Dragon Quest VII Dragon Quest VIII Persona 2: Innocent Sin Persona 2: Eternal Punishment Breath of Fire IV Shining Force Shining Force II Shining Force III Fire Emblem: Three Houses Fire Emblem Awakening Fire Emblem Radiant Dawn Triangle Strategy Fell Seal: Arbiter's Mark Disgaea Disgaea 2 Disgaea 5 Disgaea 7 Phantom Brave Makai Kingdom Valkyria Chronicles Valkyria Chronicles 4 Troubleshooter: Abandoned Children Jagged Alliance 3 Wizardry 8 Wizardry: Tale of the Forsaken Land Might and Magic VI: The Mandate of Heaven Might and Magic VII: For Blood and Honor Legend of Grimrock Elminage Original Stranger of Sword City Operation Abyss: New Tokyo Legacy Labyrinth of Refrain: Coven of Dusk Labyrinth of Galleria: The Moon Society Dungeon Siege Dungeon Siege II Dungeon Siege III Drakensang Drakensang: The River of Time Avernum: Escape From the Pit Avernum 2: Crystal Souls Avernum 3: Ruined World Geneforge 2 - Infestation Divinity: Original Sin Divinity: Original Sin 2 Suikoden Tierkreis Suikoden Tactics Eiyuden Chronicle: Rising Radiata Stories Azure Dreams Unicorn Overlord Soul Nomad & the World Eaters
>>3993215 That's pretty common in dungeon crawlers in general. Wizardry: Tale of the Forsaken Land, Dungeon Travelers 2, Demon Gaze, Elminage Original, Metro Quester, etc. The majority of SRPGs also qualify.
So far as "traditional" JRPGs go, there's also Lufia: The Legend Returns.
>>3993215 Frankly, most JRPGs don't need more. Suikoden is the exception because you get ~70 combat characters in every game. Considering you're stuck with MC that gives you five slots to play around.
Final Fantasy VI, The Genius of Sappheiros, and Tecmo's Secret of the Stars are the only games that have you use more than one party? Even if it is in a particular dungeon? Trails in the Sky 1st Chapter does something similar at one point if remember but you cannot switch parties whenever you want.
>>3993780 There are a few Trails games that have dungeons where you switch between different parties. For non-Trails games though, Tales of Graces has a dungeon where your party gets separated and you switch between them.
Suikoden has potential for kino 6v6 fights, sadly the bosses are mostly just 1 big forgettable monsters I dunno if this was different in III-V, only played I&II though