This app was mentioned in 1 comment, with an average of 1.00 upvote
I know there are Android apps like that. Can you use Android apps on a iPhone? Sorry, not sure how those work, but Google Store is open development, so they may have a version of the app that runs there.
Edit: Meh, there was just this one that does audio that I had seen, but they have no business website.
https://play.google.com/store/apps/details?id=com.michailidis.dimos.blindfoldchesstraining
Edit Edit: Google has a tool that may help though, they convert android apps to iOS, to promote development for them first. Though you have to be able to code a little anyways. Just checking what your options are.
I'm unsure if you need the code, or if an .apk file is usable. You could email the developer to see if he'd send the code if needed...