Sorry to cross post, but I just posted this in another thread asking a similar question.
If you have an Oculus Rift then definitely check out the Oculus Tray Tool made by ApollyonVR over at the Oculus forums.
https://forums.oculus.com/community/...s-hopefully/p1
It allows you to easily display the FPS hud in the headset, as well as see pixel density settings (super sampling), and also toggle Asynchronous Space Warp. The reason it's awesome is because he has added in voice commands, so you can use the microphone in your Rift to toggle this on the fly. I use it all the time to check FPS and how much spare capacity my rig has, then toggle it off again so it's not in my vision.
It's not as good as a permanent FPS counter, but it's a great option to at least check FPS that works in every title. Being able to toggle it on and off quickly with just a couple of words is amazing.