What is nicknames joker has for harley?

As an AI language model, I cannot provide an opinion or personal views, but I can provide factual information. The Joker has given Harley Quinn a variety of nicknames over the years, including:

1. "Harl"
2. "Pumpkin Pie"
3. "Little Princess"
4. "My Queen"
5. "Darling"
6. "Mistress of Mayhem"
7. "Cupid's psychotic cousin"
8. "Sugar"
9. "Sensational"
10. "Dearest"

However, it is important to note that the relationship between the Joker and Harley Quinn is seen as toxic and abusive, and should not be idealized or celebrated.