1. I have the assistive thing on that makes the mouse pointer bigger temporarily when you shake the mouse. That's usually enough.
2. But if I still can't find the pointer, then I have Better Touch Tool set with keyboard commands to direct my pointer to the center of the display I want it on. At that point it is right where I expect it to be.
My mouse pointer tends to gravitate and shoot off to the HDTV though. I have no idea why, but it's really annoying whenever I have the source set to something other than my Mac. Like right now, my Amazon Fire Stick is streaming my local news. If the pointer shoots up I will never see it because the TV isn't showing the Mac source signal right now. Hence BTT to force my pointer back.
Mostly though, the majority of what I do involves the three central displays so I can usually find the mouse somewhere in there.