I’ve found several of these running accessories to be helpful:
Spibelt to carry vital items during a run or race: energy gels, keys, credit card / ID, etc.
Water belt (in many of these you can also carry same items as listed for Spibelt)
Headlamp and reflective gear – to light your path and be visible for night running
Metronome: see more info about this at Chi Running. I’ve found that wearing a metronome during training and racing runs is very helpful in maintaining a strong (180) steps per minute cadence, especially at end of long runs.
Road ID – excellent to wear to be a permanent identification badge for you whenever you run. Lists your vital information and contacts. You can also buy “badges” to include on this ID bracelet for inspiration or remembrance.