The Debut feature set provides both a specification for building standard features that will integrate well on any site and a set of features built to that specification.
Debut comes out of the Open Outreach distribution. Rather than building features highly customized and limited to the specific use case of nonprofits, with attendant assumptions and dependencies, Open Outreach developers decided to base their distribution on a generalized set of features that, while meeting the needs of Open Outreach, would also be applicable to diverse other use cases. Specifically, Debut features are written so as to integrate easily and seamlessly into any Drupal site or distribution.
See the Debut project page for a current list of Debut features.