Cora/Ramsley (The Haunted Mansion) — Heart Butler
Not romantic, more two people with a common goal (power) and ideal (“Love is weakness.”). Both prevented their child/child figure from marrying for love beneath them by killing said love (Daniel/Elizabeth). I can imagine them working together to get into seats of power.
I’m surprised I didn’t see this here: ReginaGeorge, even if only for the Mean Girls reference.