Bold are the only ones I'm likely to change playthrough to playthrough:
MC: 1st playthrough Tav HWElf Arcane Trickster Rogue / 2nd Playthrough Durge Open Hand Monk
Astarion: Swords Bard
Lae'zel: Battlemaster Fighter
Karlach: Wildheart Barbarian
Shadowheart: Light (after Trickery) Cleric
Wyll: Fiend/Blade
Gale: Evoker
Minsc: Hunter Ranger-Knight
Jaheira: 1st playthrough Gloomstalker, 2nd playthrough Land Druid
Minthara: Vengeance Paladin
Karlach, Shadowheart, Wyll, Minthara, and Minsc feel too tied to their class and subclass for me to change, and Gale I could probably try other subclasses.