Guitarix - Guitarix is a simple Linux Rock Guitar Amplifier for https://alternativeto.
Serum - VST for FL Studio, Ableton Live, and many other VST supported DAWs. Heavily utilized in EDM.
TH-U - World class guitar amps and effects for PC and Mac
Omnisphere - Piano, pad and synth VST for DAW's.
Ampire - State Space Modeled guitar amp/cab/stompbox simulator.
Korg Legacy Collection - Korg Legacy Collection is a suite of VST instruments that acts as an audio plugin software for integrating synthesizers and effects units into your digital audio workstation.