Tashas clerics (order, peace, twilight) and life cleric are all amazing, borderline broken synergies.
IMo the ranger choices would be really fun and mechanically strong. Like a swarm keeper dip.

Rogue is a good 2 lvl dip for cunning action. Artificer is an ok dip (more temp hp and support). Then of course a conjuration wizard really expands the spell list.

Shepherds kinda want to get to lvl6, then maintain spell slot progression, but really don’t benefit that much from either staying single class or multiclassing, so the rest is all kinda a bonus.