I wrote a ton, like most people. The most complex ones would have to be Tax Helper, an extensible accounting tool to get my taxes done in a minute: https://github.com/DexterLagan/tax-helper

Another one I'm sorta proud of being the only one using is Invoicer, a one-click invoicing app: https://github.com/DexterLagan/invoicer

Last one I'd consider strictly personal would be Todo Master, an advanced todo with calendar, preset/macro facilities for generating dev reports and tons of other features only I would find a use for: https://github.com/DexterLagan/todo-master

Oh wait, there's also Database Master, born out of frustration with MySQL Workbench: https://github.com/DexterLagan/database-master

As far as I know, most if not all of my github repos are only used by myself.

Cheers