I work for an HR compliance training company and we use a heavily modified version of Moodle in combination with our own back end. Moodle was originally chosen as an MVP for the company and it is good at playing industry-standard formats, like SCORM and AICC. But Moodle's code base is around 20 years old and very cumbersome to modify so we do plan on moving to 100% custom in the future.
I have a small filing cabinet with tabbed, labeled folders for each area of my life: house (mortgage, insurance, etc), me, my wife, car insurance, etc. It's old fashioned but it works incredibly well. Anything I may need to access away from home also gets scanned into Evernote.
I built a tool to help realtors easily create slideshows from still photos without any technical knowledge.
It hasn't really gotten a lot of traction and there are probably other markets where this might be useful, but I've been so busy with other stuff lately.