Transcribe - An online app that reduces the pain of converting audio & video to text. Saves thousands of hours every month for journalists, lawyers, students and professional transcriptionists all over the world, including researchers in Antarctica.
Serum - VST for FL Studio, Ableton Live, and many other VST supported DAWs. Heavily utilized in EDM.
Neuratron AudioScore - Polyphonic Music Recognition Software. Neuratron AudioScore Ultimate music transcription software.
Surge XT - Open-source subtractive-hybrid synthesizer formerly sold commercially as Vember Audio Surge.
Audiveris - Audiveris is an open-source Optical Music Recognition software which processes the image of a music...
Vital - Vital is a spectral warping wavetable synthesizer with drag'n'drop modulation workflow and animated preview of the synth's inner workings where needed. Comes with many modulation sources (including audio-rate), MPE support and FX chain.