Do not ride without a helmet.. this is for your safety..
2) Puncture kit,
If you are doing a long ride, have a pucture kit and learn how to do a patch or change a tube.
Cyclists do need a headlight. This helps to when the road is full of potholes or you might have random people waling in the highways.
4) taillight and reflector,
Night rides are always dangerous without a taillight or a reflector vest. numerous accidents have been recorded due to cyclists not being visible to the big vehicles.
Hydration becomes a very important part when you are on a long ride.
Lot of new riders are not aware of this. Wear cycling shorts to save your butts.
7) a Good horn,
Bell or horn will be necessary in the city rides.