What kind of exemplars are you looking for? Many of the levels have example solutions with them to show how you might go about completing the level. You need to be a verified teacher to access them. If you are a verified teacher (and everyone who went through PD should be) then you would see "Example Solution" as a blue button in the blue teacher panel that pulls out from the right on any level. See picture below for example.
Another good resource would be the game lab documentation which is a great reference with example code segments for many of the concepts. You can see the documentation by clicking see examples on any block in the tool box or by going to: https://docs.code.org/gamelab/.
Hope that helps! If you share more of what teachers are struggling with I'm sure others can offer more suggestions.