JUCE is an open-source cross-platform C++ application framework for desktop and mobile applications, including VST, VST3, AU, AUv3, RTAS and AAX audio plug-ins.
Enhanced version of Cockos' iPlug - A simple-to-use C++ framework for developing cross platform audio plugins and targeting multiple plugin APIs with the same code. VST / VST3 / Audiounit / RTAS / AAX (Native) formats supported. NOTE: THIS IS OBSOLETE, PLEASE SEE IPLUG2:
Collection of audio effects plugins implemented from the explanations in the book "Audio Effects: Theory, Implementation and Application" by Joshua D. Reiss and Andrew P. McPherson.