Sibelius - Sibelius is a virtual score creation tool which allows composers to easily create new piano scores, developed by Avid.
Guitarix - Guitarix is a simple Linux Rock Guitar Amplifier for https://alternativeto.
MMA - “MMA—Musical MIDI Accompaniment” is an accompaniment generator.
Ampire - State Space Modeled guitar amp/cab/stompbox simulator.
Synfire - The comprehensive Music Prototyping Studio for professionals and enthusiasts.
TH-U - World class guitar amps and effects for PC and Mac