GTD is a productivity system created by David Allen that involves capturing everything, organizing tasks into projects and context, breaking down tasks into actionable steps, and having a regular review process. However, it can be overwhelming for those who don't need all the bells and whistles. Alternative systems include Autofocus, Strikethru, Getting Sh-t Done (GSD), Day, Week, Month (DWM), and Final Version, which offer simpler approaches to task management. These systems can help individuals prioritize tasks, manage their time, and increase productivity without feeling overwhelmed. They are designed to be adaptable and can be applied digitally using various apps and tools.