Add-ons for Sibelius which are currently or have previously been available include extra sound libraries, extra plug-in features (which are free of charge, and often created by Sibelius users), full versions of the PhotoScore (scanning) and AudioScore (microphone input) software, keyboards and keyboard covers showing shortcuts, and Sibelius-branded merchandise.
A range of software for teachers and students from the same company, Sibelius Educational Suite, is not directly connected with the Sibelius program, but is often used by the same people.