The following website by Augsburg University contains one of the most comprehensive lists of assistive technology we've found. They provide products in the following categories: reading & literacy support, writing support, note taking support, dictation/speech-to-text/speech recognition, mind mapping & brainstorming support, study skills & aids, organization & task management support, time management & distraction free support, research tools, stress management and relaxation, vision, hearing and auditory support, communication and built-in accessibility. 

Free/Low Cost Assistive Technology