I really like the idea of collecting highlights into a separate document. I could see a lot of uses for this in curating great ideas from a document into your own space.

Texthelp Study Skills – Google Docs add-on

Use Texthelp’s Highlighting Tools to highlight key areas of your document to collect, group, and learn from later. Simply select and highlight the desired text and click “Collect Highlights” to extract it and place it in a new document (by color or location) for students or educators to review.