PhoneGap is hybrid HTML5 mobile application framework which has nicely growing user community.
In fact, any other developers using PhoneGap framework can just import your plugin and use the functionality in their own apps. Developer community has created many such plugins. And Cordova contributors have developed plugin manager called plugman in order to make installation of plugins simple.
There are several plugin repositories which collect and archive PhoneGap framework plugins.
While working with iOS and Android applications I have used several PhoneGap plugins and want to share some of them which helped me a lot in mobile app projects. Did I miss any good ones?