I had ben looking for an accessible app that would allow me to monitor information about my system such as fan speed, temperature, CPU load, etc. I had tried several times to request the developer of iStat Menus consider accessibility without any success. I learned about MenuBar Stats, https://seense.com/menubarstats from listening to the Mac Geek Gab podcast, http://www.macobserver.com/tmo/features/mac_geek_gab/.
I downloaded the trial of MenuBar Stats and found it was not accessible. I reached out to Fabrice, the developer of MenuBar Stats and within hours he had made the app pretty accessible. Here is a blog post he wrote about his experience, https://seense.tumblr.com/post/144353903400/seense-and-accessibility. Please note that for now he has two versions of MenuBar Stats. He has created a version that is compatible with Voiceover, https://seense.com/menubarstats/voiceover/ and the plan is to merge the VOiceOver accessibility changes with the next major release of MenuBar Stats. Please be aware the accessible version is not in the App store yet. Fabrice also plans to make accessibility enhancements to his other apps.
I really like MenuBar Stats and it provides all the information I was lookng for.