Super Simple Highlighter
An extension for Chrome that makes private highlights on any web page, and attempts to restore them on subsequent visits.
An app for Android that re-implements Apple’s AirPlay® protocol, allowing your device to become a audio receiver. Also includes recording, and real-time effects.
Any software I've written that you didn't pay for should be considered unsupported (though I'll try).
I've written other things, but to be honest I've forgotten most of them. So if you find one in the wild, consider it unsupported as well.