Mixxx - The most powerful free DJ software in the world.
AmpliTube - Guitar Amp & FX modeling plug-in • Amp, Stomp, Cabinet + Mic, Rack FX modeling
VirtualDJ - Virtual DJ Software - MP3 and Video mix software for DJs
Guitarix - Guitarix is a simple Linux Rock Guitar Amplifier for https://alternativeto.
TH-U - World class guitar amps and effects for PC and Mac
Ampire - State Space Modeled guitar amp/cab/stompbox simulator.