I don’t know that there are any that make cut sections like Skalp. I realize that is the opposite of answering your question, but that is my understanding.
From a technical standpoint, Skalp creates a shape based on the section cut and fills it with your pattern of choice, and then places the face of that shape a millimeter or so back from the section cut so that it shows up. It’s pretty impressive, to be honest. Then it associates that with a particular scene, and only shows that geometry when that scene is selected. Plus it allows you to fill with your selection of patterns, and even allows you to create them. So as far as I know, it’s unparalleled.
That out of the way, check a few of these out for comparison:
[Super Section] - I used it before Skalp was released. Works well without layout.
[SectionCutFace] - never used it, but has some similarity with the others
[Solid Section for SketchUp] - from dibac
Last but not least, [CONDOC tools], which is a different take on section cuts for construction documents, but well worth a look. The level of organization and efficiency I find pretty incredible. It’s the one I might have used if I was doing more architecture and less manufacturing.
Those are my thoughts, but what are you trying to use this for? Pro or hobby? Houses or Skyscrapers, etc.?