Heading Structures - do titles and section headings use a consistent style?
Do images have alt tags or captions?
For videos, are the correctly closed-captioned, or presented with a correct transcript?
For audio recordings or podcasts, are they accompanied by correct transcripts?
Color - are high-contrast colors used for easy visibility?
Color - is color-coding avoided, or is at least enhanced by another indicator such as bold or underlining?
Fonts - is a consistent, sans-serif font used?