Lights: Very bright, 300 lumens
helmet light and down tube light
Cameras: able to read licence plates in the next lane, long lasting batteries (more than two hours), spare batteries and separate charger, keep timestamp and settings when changing batteries.
Horn: Loud sounding like car horn. The Hornit is lousy.
Mechanical odometer that attaches to front fork. Speedometer not required - there are plenty of apps for that.
Mirrors: lightly convexed, attached to inside of handlebars for straight handles, drop handles, etc.
Rear proximity sensor and alarm to warn drivers who are too close.