North York, 1972-1985 (top), 1985-1997 (bottom)
The Borough of North York upgraded to the City of North York on Valentine’s Day 1979, and from then on it used the excessively cutesy motto, “The City With Heart”. Hearts featured all over official signage and whatnot, and in 1985 they finally made their way onto the flag.
Unlike the Scarborough and East York, which still occasionally fly their flags in an unofficial capacity, North York dumped its flag when it amalgamated with the City of Toronto in 1997. Most people probably don’t even remember either of these existed.