Many gamers have setups with two or monitors. Oftentimes these differ in size, resolution, even aspect ratio. They can be very helpful in productivity tasks, but mid-gameplay they rarely serve as more than displays for external music or chat.
Are there games that utilize this extra space in a unique way and are played better or exclusively with two or more monitors? Preferably something more than just extra FOV
Not really, it conflates games that have some ability to spread one screen between to monitors and games that actually utilize two monitors.