This is an interesting idea but I'm having a hard time coming up with a good answer
I think I would definitely lean toward side quests that are physically hard or impossible to do (for some people)? Surely there's something that doesn't respect colorblind people. I know I was never able to do the lightning bolt thing in Final Fantasy X because my reaction speed just wasn't physically fast enough, and surely people with motor issues ran into that problem there and with other side quests.
I'm Rose Coldsteel, from Legend of Coldsteel