General dyslexia writing guide. Lots of important considerations to writing with a dyslexic audience in mind, including letter and text spacing

One of the most important things about accessible writing is using an appropriate font. This resource Includes a short list of some dyslexia friendly fonts, like Comic sans, Arial, sans serif fonts, verdana, Helvetica, and century gothic

Colorblindness design primer; covers some essential basics.

Super thorough detailed colorblindness design guide. Suggests palettes and what to use vs what not to use to make clear graphics for colorblind audiences. I personally rely on heavy contrast, blue and red central colors (avoid red + green or yellow + white combinations) for any colors that must be distinct, and never rely on colors exclusively to denote concepts- include labels or textures to visually distinguish aspects of graphics that must be distinct, not just color.