ThreadBoard
A quiet place for the loose threads you carry around in your head.
ThreadBoard is a small, private notebook for thoughts that would otherwise rattle around all day. Catch each one, file it under a theme, star the ones that matter, finish them, move on. Three at a time is the limit, on purpose.
For Mac, iPhone, iPad, Android and Windows. No account, no server, no tracking, and it works fully offline. Paid once, with no subscription.