Guitarix!

Guitar Rig is a guitar multi-effects processor software developed by Native Instruments. It is sold either with a pedalboard hardware controller called Rig Kontrol, or the software only. This software can be used as a stand-alone application or as a plug-in of different DAWs.

Guitar Amp & FX modeling plug-in

Impro-Visor (short for “Improvisation Advisor”) is a music notation program designed to help jazz musicians compose and hear solos similar to ones that might be improvised. The objective is to improve understanding of solo construction and tune chord changes. There are other, secondary, things it can do, such as improvise on its own. It has also been used for transcription. Because rhythm-section (e.g. piano, bass, drums) accompaniment is automatically generated from chords, Impro-Visor can be used as a play-along device. Now having a wider array of accompaniment styles, its use is not limited to jazz. »

Rakarrack is a richly featured multi-effects processor emulating a guitar effects pedalboard. Effects include compressor, expander, noise gate, graphic equalizer, parametric equalizer, exciter, shuffle, convolotron, valve, flanger, dual flange, chorus, musicaldelay, arpie, echo with reverse playback, musical delay, reverb, digital phaser, analogic phaser, synthfilter, varyband, ring, wah-wah, alien-wah, mutromojo, harmonizer, looper and four flexible distortion modules including sub-octave modulation and dirty octave up. Most of the effects engine is built from modules found in the excellent software synthesizer ZynAddSubFX. Presets and user interface are optimized for guitar, but Rakarrack processes signals in stereo while it does not apply internal band-limiting filtering, and thus is well suited to all musical instruments and vocals. Rakarrack is designed for Linux distributions with Jack Audio Connection Kit. »

Noteflight is an amazing online notation editor. On the free version you get 10+ instruments to choose from, lots of musical symbols and more. On the payed version (Cresendo) you get lots more instruments, guitar tab and sharing options. Best way to wite music on the web.

TabIt is a full-featured program for creating, playing, and printing guitar, bass, or banjo tablature.

Band-in-a-Box is so easy to use! Just type in the chords for any song using standard chord symbols (like C, Fm7, or C13b9), choose the style you'd like, and Band-in-a-Box does the rest... Band-in-a-Box automatically generates a complete professional-quality arrangement of piano, bass, drums, guitar, and strings or horns.

TabToolkit for iPad, iPhone and iPod touch is an incredibly powerful music notation viewer with multi-track audio playback. The app includes an audio synthesis engine that enables you to listen to and control the audio for all instrument tracks individually. TabToolkit makes learning how to play your favorite songs on guitar, bass, keyboard, drums and other instruments easier and more fun.

Amps and effects done right, right on your Mac. Beautiful, immersive, powerful, audibly wonderful.

BIAS FX is a world-class, guitar amp-and-effects processor for desktop and iPad use. It gives you an endless collection of insanely great-sounding guitar pedalboards, ultra-high definition stereo rack effects, dual amps and dual signal chain.

GNUGuitarINUX is a live lightweight GNU/Linux distribution for guitar players. It is configured to obtain the best performance with the smallest latency possible. GNUGuitarINUX has several dedicated programs but rakarrack is its main target.

Tabular is a brand new tablature editor that lets you read and write music for guitar, bass, drums and much more. It's the best way to learn new songs, write your own songs and run through practice exercises for nearly any kind of stringed instrument or drum kit.

Deplike is a portable Android guitar amp and guitar effects processor, a full-featured guitar rig in your pocket.

A complete set of 36 effects for guitar, bass or vocals.  Audiffex guitar pedals - the legendary product, released under the previous label DSound 15 years ago. Pedals are exact models of real hardware devices. The set contains effects, amp models, cab models and a tuner.

Busker is a complete set of tools to create musical arrangements from sheet music (chords + melody staff). It uses Yamaha compatible styles (thousands can be downloaded for free) for auto-accompaniment. Once you entered the song you can easily play it with many different styles and try different multivoices with auto-harmonies.