The Paladin is one of the most self-sufficient classes in Baldur's Gate 3, combining support, weapon damage, and magic in one heavily-armored package. When it comes to multiclassing a Paladin, the best strategy is to build around its Divine Smite feature, mixing in a full caster to increase the amount of spell slots available. While any full spellcaster class can fulfill this role in Baldur's Gate 3, the best choice is a class that shares the Paladin's need for high Charisma, such as the Sorcerer, Bard, or Warlock.