>>148973308
Leonardo (which I'm sure you knew), and Mona Lisa.
Purely a fan fictional ship, as far as I know. Some fans portray them as a couple in fan art and (more rarely?) fan fiction.
In the 87 series she made her only appearance in a Raphael-centric episode, but wasn't really with anyone. The very end has her make an appearance in the Turtles' lair, but she was never seen again.
In the 2012 series, she appears as a member of an alien species. She barely interacts with the Turtles, except for Raphael, with whom she eventually shares a kiss. She appears in five episodes, is mentioned in one, and appears as an illusion in another.
In the IDW comic, she doesn't really have a relationship with any of the Turtles, except Donatello, with whom she was flirted and kissed on the cheek. This at least makes more sense than Raphael, since she's an intellectual, and Raph is at best a wisecracker in the toons, and a violent, emotionally retarded, jackass in some of the comics and movies.
Interesting facts: Mona Lisa was supposed to be a female turtle, in the 87 series, but Eastman and Laird were still both involved in TMNT, at the time, and said no to that, because they both thought adding a female turtle was dumb and lacking creativity.
Mona Lisa is named after a piece of Leonardo da Vinci's art, but has never had a relationship with Leo in any of her iterations.
She's apparently the only official girlfriend of any of the Turtles... though I think the apparent forever alone status of Leo, Don, and Mikey only applies to the 2012 series, where she was with Raph.
