It’s so great to read all your inputs on all of our song choices @MissInkBlot! 
Yeah Ozzy is a bit of an acquired taste, and there are only a few of his songs that pop up every now and then when I am shuffling through and listening to my music. Looking at the ones that I do have, they would fit possibly for another Joker/Harley Quinn mixtape. 
First up, this one now thinking about it, could have fit in our “what party songs Joker would hate mixtape.” Especially when it would lead Joker into a false sense of security thinking it will go his way when the lyrics go, “Crazy, but that’s how it goes. Millions of people living as foes. Maybe, it’s not too late… To learn how to love and forget how to hate.”
Next is one that I listen to when I do cardio workouts. Mainly for its high energy tempo that I like to keep me going.
It might also be something Harley listens to especially when these lyrics are sung: “Make a joke and I will sigh and you will laugh and I will cry.”One final one is this one and it’s a bit more of a recent one of his. Hearing the lyrics makes me think of Harley thinking about her time with the Joker and what she will do now once she’s split from him.