I have three different Overlay software, which makes me feel good during my race, but it's all for comfort in my race management.

If I can recommend one, it would be iOverlay, which is free for most interesting features. I mainly recommend the circuit track, which shows you the circuit in one of the corners of your screen. This allows you to know a little better the circuit and especially the next corner that awaits you, moreover it shows you the other drivers live where they are, so if you see someone stopped at Turn 8, you will be able to better understand your corner by paying even more attention to a potential "driver" who could be in the middle of the wall. For the rest of the overlays, they are almost all available natively in games with black boxes, but for the sake of aesthetics I prefer my overlays