As it turns out, Bionic Reading isn't all that special, it's just a bunch of CSS hackery. This is an open source version that, theoretically, could be turned into a browser plugin or added to a website.

Fonts Changer allows users to change fonts in the browser. Chrome’s advanced font settings let users change system fonts in your browser using the Fonts Changer. Over 80 fonts available for your Chrome browser.

A collection of applications able to interact with websites, without requiring the user to open them in a browser. It also provides well-defined APIs to talk to websites lacking one. Automate access and extraction of data from websites that don't make it easy or possible. Has applications for adding accessibility to sites that are unfriendly to the visually impaired. Tries to focus on quality of results. Multiple interfaces.

A plugin for Bootstrap 3 that automatically implements accessibility best practices (such as being friendly to screen readers and color schemes).

OpenDyslexic is a font which was designed to mitigate some of the difficulties posed in reading by dyslexia. Several variants (bold, italic, et cetera) are included in the files. The font is free - the only requirement is that you acknowledge that the font is OpenDyslexic.