I made a personal research database of art works and historical events as part of my #S_T_Gill project. It allows for testing of theories and conclusions. It also generates (html) material for the project webpages and content for the digital maps.
The database evolved over years and was more about making progress than good design. I wasn't happy with it. So this year I've been redeveloping it from scratch with a view that it could be used again, by me or some other researcher.