TabToolkit is described as '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' and is an app in the audio & music category. There are more than 25 alternatives to TabToolkit for a variety of platforms, including Windows, Mac, Linux, iPhone and iPad. The best alternative is MuseScore, which is both free and Open Source. Other great apps like TabToolkit are TuxGuitar, Guitar Pro, OpenMPT and Rosegarden.
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.
Songsterr is an archive of guitar, bass and drum tabs. It is collaboratively built and maintained by your fellow music lovers. Anyone with Internet access can contribute new tabs and make changes to existing ones.
Power Tab Editor is a free tablature authoring tool created by Brad Larsen for Windows. It is used to create guitar, bass and ukulele tablature scores, among many others. The current version uses the *.ptb file format.
Band-in-a-Box is an intelligent automatic accompaniment program. You can hear and play along to many song ideas and go from "nothing" to "something" in a very short period of time with Band-in-a-Box as your "on demand" backup band.