A system for novel-writing. Mostly just lets people set variables and intelligently refer to them within the text. This would require localization-like ability to adjust the case and number of the variables. Could provide a user interface that makes this easier for certain classes, e.g. Character, Location, Event, Relationship, etc.
I've been using a combination of Gramps, Kate, and a Python templating engine called Chevron, plus a JSON data file, to achieve much of this effect. But Gramps and the JSON file have the potential to come into conflict.
Due to the GPL2+ license of Gramps, it would be difficult to make use of it directly. If we could read the Gramps database we could leverage that, but it would be nicer to have an integrated solution.
Rust + Azul GUI toolkit might be a good option to build the data processing and the UI in one place.