General:
* Sketcher: This is the most straightforward and common term.
* Artist: This is a broader term, as sketching is just one aspect of art.
* Illustrator: This term is used if the sketches are intended for specific purposes like book illustrations.
* Drafter: This term applies if the sketches are technical drawings.
More specific:
* Urban sketcher: Someone who sketches scenes in public spaces.
* Fashion sketcher: Someone who sketches clothing designs.
* Architectural sketcher: Someone who sketches building designs.
The best term depends on the specific type of sketching and the context.