Helmet light. 300 lumens. So you light up what you are looking at. 300 lumens will light up an unlit trail at night. Rear helmet light that flashes.
Reflector straps for your wrists and ankles and a reflector vest.
Mirror. Convex but not extremely convex. If it's too convex you can't see the car approaching from behind you until it's just over your shoulder - that's too late.
Horn. Loud. Airzounds is affordable. If you can, get one that sounds like a car. I don't like the Hornit. The pitch is feeble and it's only sounds loud when you're testing it in the store or in your garage. It's feeble on the road. And get a bike bell to alert pedestrians with a friendly ring.
Camera. With resolution that can read license plates in the next lane. Enough battery power for more than an hour, preferably more than two hours. Make sure spare batteries and a separate charger are available. Make sure that camera settings like timestamp are retained when changing batteries so you don't have to reset it all the time.
Bag. Panier or trunk so you can bring stuff with you like food, rain-gear, tools, spare tube, pump etc.
U-Locks. Lock both wheels.
Eye and mouth covering like sunglasses to protect your eye and glasses from dust getting in. Mouth covering because sometimes you swallow bugs.
Have fun.