Welcome to the school of rock. A Mac-sized practice space. Your own recording studio. If you want to learn to play an instrument, write music, or record a song, GarageBand can help — whether you’re a rookie or a rock star.
Carla is an audio plugin host, with support for many audio drivers and plugin formats. It has some nice features like automation of parameters via MIDI CC (and send output back as MIDI too) and full OSC control.
SAVIHost lets you basically turn a VST instrument plugin into a standalone app. It's a very simple VST host that loads up a similarly named VSTi dll file and lets you interact with the plugin as if it's been loaded into a DAW complete with keyboard and extensive options...
Everyone want to have music to their videos, so why not creating it yourself? Even with ZERO knowledge of music, anyone can put together their own special soundtrack by using MyMotif’s sounds, melodies and beats.
NanoHost is not a synthesizer. It is a free, minimalist host application for Windows that can load VST-synths. Furthermore, it can act as a wrapper which converts VST-synthesizers into standalone applications.
A VST (plus AudioUnit on OSX) plugin host designed for live use. Based on the JUCE 'audio plugin host' code, heavily modified to better suit my purposes.
Metaplugin is a plugin that loads other plugins. As simple as that. Build your own effect networks with this plugin wrapper using any VST/VST3 (and AU, if you’re on Mac) effect you already have on your harddisk.
Blue Cat's MB-7 Mixer is a unique plug-in that splits the signal into several frequency bands and lets you re-mix and process them as if they were separate tracks: change levels, apply panning, add built-in effects, or even third party plug-ins.