So, crossovers.
Sabrina, as a character, is very tied to the PMMM setting - everything about her origins, her power, even her name are tied to her mission and goal in PMMM.
While there's definitely some fun to be had by dumping her into a different setting and seeing all the incongruities pile up, there's a different approach too: A story about a character that is to the new setting as Sabrina is to PMMM.
So, as an example, for RWBY the Sabrina-equivalent would probably have a mission to stop the constant assault on the kingdoms, and would have Grimm-controlling powers.
The parallels work best in settings with large-scale systemic issues that need to be fixed, of course.