Can't find Blueprint-Derived classes using asset registry in 4.17?

I did something similar. Collecting all blueprints and even their Functions, so i could have a fully customizable/moddable platform.

Maybe


SearchFilter.bRecursiveClasses = true;

will help you.
But you have to remove


SearchFilter.ClassNames.Add(UBlueprint::StaticClass()->GetFName()); SearchFilter.ClassNames.Add(UBlueprintGeneratedClass::StaticClass()->GetFName()); 

then. PS: for the forum maintainers: the new editor sucks big time when you copy/paste code. (running firefox 55.0.3)