2 STI levers on all my road bikes and gravel bike and an out front garmin mount on all.
So 3 things on my road bikes.
Gravel bike has 4 things since a small bar bag is attached.
Commuter?...GPS mount, 2 brake levers, and 2 bar end shifters.
So 5.
I add a light sometimes, but it doesn't stay on any particular bike.