While reviewing Itch.IO documentation, I stumbled across an excellent paper on developing games to be friendlier towards disabled players. It is an excellent read on the subject, and I would recommend reading the article if you have the time.
I think part of the difficulty of considering someone with a disability is that there are so many different types of disabilities out there. Each one has its own challenges and possible solutions. For example, Color Blindness, Amputees/Restricted movement, Epilepsy, deafness, Cerebral Palsy, and many others could affect someone's ability to play a game and solutions to each set of problems is different.
Here is the link to the article: http://includification.com/AbleGamers_Includification.pdf.
Anyways, this doesn't really belong in any of the forum sections, so I thought C# was the best place for it.