BARD, the Braille and Audio Reading Download from the National Library Service for the Blind and Print Disabled (NLS), is a web-based service that provides access to thousands of special-format books, magazines, and music scores.
Bookshare makes reading easier. People with dyslexia, blindness, cerebral palsy, and other reading barriers can customize their experience to suit their learning style and find virtually any book they need for school, work, or the joy of reading.
A site (and mobile app) that allows you to type in a problem (or take a photo of it on the app, including handwritten!) and get step-by-step-solutions.
Mathway provides students with the tools they need to understand and solve their math problems. Use the menu in the top left corner to switch between subjects.
Rewordify is an online application (rather than an app or software) that simplifies the language on other websites or text pasted into a text box on their site.
Snap&Read and OrbitNote, together, offer the most complete toolkit to help students comprehend everything they read with tools to assist reading, organize information, and annotate PDFs.