If I had to make a list from less "Cares" to more "cares", it would be like that.
Joker (Comic, DCAU, Arkham and Gotham) --> Voldemort --> Joker (The Batman, 2,004-2,008) --> The Joker (Telltale game, Vigilante Route)---> Joker (Jared Leto) -> Joker (Telltale game, villain route)
-The Joker of the animated series of 2,004 still does not love Harley, but has a slightly greater care.
-The Vigilante Joker of the telltale games loves Harley, but ends up betraying her in the end.
-Jared Leto Joker really seems to love Harley, and even saves her from prison at the end.
-The villain Joker of the telltale games, really loves Harley Quinn.