Guitarix

• 1 Guitar Amp
• 25 built-in modules including stuff from a simple noise gate to brain-slashing modulation f/x like flanger, phaser or auto-wah
• Noise Gate, Compressor, Mono Level Output, and Clipping
• Tuner
• Rack: Tube Selection, Pre-Gain, Master Gain, Clean/Dist Blend, Drive, Optional Bass and Presence Boost, Optional Reverb, and a Large Master Volume
• Limiter
• Amp Impulse for Manufacturer Characteristics, Cabinets, EQ
• Stereo FX, Reverbs and Delays, Cabinet IRs
• Additional Third-Party Plugins
• Support for AIDA-X models (RTNeural format) has been included since version 0.45.0.
• see the plugins of MOD Audio

macOS: Limited to older builds or currently available via Guitarix.vst (as a VST3 plugin). 

Windows: No official standalone version, but usable as a VST3 plugin via Guitarix.vst.

Guitarix is available on GitHub from brummer10. 

NeuralRack and more

brummer10 has other effects available on GitHub: 

• ToneTwist Plugs (several plugins, such as the BOSS MT-2 Metal Zone, overdrive pedal, bass fuzz pedal, and more)
• NeuralRack (NAM and IR Loader)
• Neural Amp Modeler LV2 GUI of neural-amp-modeler-lv2 by mikeoliphant
• SmoothIR
• for all repos see the overview

Blog article at GearNews (german).