Something like GeForce Experience for OS X I'm looking for an application like GeForce Experience but for OS X : a software that configures my games depending on the configuration of my Mac.

I think there is nothing like that for OS X, so do you know a web site who lists the recommended settings for games on Mac ?
I dont believe there is such an application, the only thing i can think of is if you're using a macbook pro with an nvidia card, you can install an application called gfxCardStatus (https://gfx.io/) which shows you if its using the integrated graphics card or the nvidia one, it also allows manual override of the setting.