Plugin that adds support for searching multiple sources, such as files, buffers, and registers

The unite or unite.vim plug-in can search and display information from arbitrary sources like files, buffers, recently used files or registers. You can run several pre-defined actions on a target displayed in the unite window.

The difference between unite and similar plug-ins like fuzzyfinder, ctrl-p or ku is that unite provides an integration interface for several sources and you can create new interfaces using unite.