Tesseract - Tesseract is an optical character recognition engine for various operating systems

Deepgram - Search engine for speech

Onlineocr.net - Free Online OCR service allows you to convert PDF document to MS Word file, scanned images to editable text formats and extract text from JPEG/TIFF/BMP files

Hidden Markov Model Toolkit - Hidden Markov Model Toolkit (HTK) is a portable toolkit used for speech recognition research, speech synthesis, character recognition and DNA sequencing.

Prizmo - Prizmo is a scanning application for Mac with Optical Character Recognition (OCR) in over 40 languages with powerful editing capability, text-to-speech, and iCloud support.

Jasper - Jasper is an open source platform for developing always-on, voice-controlled applications.