One accessory I probably need right now is something to beep loudly at me if I forget to zip up my saddlebag before starting my commute. This morning, I did just that, and in the last 2km of my 27km commute heard things falling out of the saddlebag. I turned around to see what happened, and found that my wallet had fallen out. I put that back in, but then realised I couldn't find the key ring with my house keys, and (more importantly right then) the keys to the shower/locker room and my locker at work. I spent the next few hours sulking in my cycling gear at my work desk, then discovered my key ring had settled to the bottom of my saddlebag where I couldn't immediately see it. Up to then, I'd been making preparations to get a new shower/locker room and locker key, new house keys, etc., and was feeling a bit annoyed with myself

.
I was very, very lucky: the wallet might have fallen out some time during the previous 25km and I might not have noticed if I was going downhill with the wind in my ears.
What would be nice is an alarm connected to an accelerometer and to my saddlebag zipper, so that when the zipper is undone *and* the device detects that I'm moving, it will beep loudly at me, as if to say "Zip the bag up, you dopey idiot!"
