Best find was a multi-tool with chain breaker. Various lights. Second-most useful was a rubber mallet.
I always try to find the owner by posting on a local forum or leaving a sign up at the point of fiinding.
* Most irritating was a bike computer the owner didn't pick up for months. I had to hassle him to come and get it.
* Most rewarding was an expensive kids wetsuit that I found while surfing at Harbord/Freshwater - they were so grateful to get it back.
Cash rewards I turn down but when they've gone to the trouble to buy a gift it feels rude to decline.
Last night I found a MyBus3 Travel10 ticket on the pavement at Wynyard - unused! Unfortunately no way to confirm the bona-fides of the owner with that one.
Lost items? My Garmin 705 disappeared off my stem when I had to bail out of a near-OTB in a 4-hour race at Yellowmundee mtb circuit beginning of last year. Didn't notice until I was part-way around the circuit. I finished my lap, got my temperature back down with the ice bag (it was a 43C day) and was about to head out to go look when an announcement came over the race control PA that one had been handed in - it was mine! Yay!
Almost as good as getting it back was removal of the prospect of having to explain to the Minister for Finance that it had been lost.
Would have been nice to find the hander-innerer and share some of the booty I won for our podium placing.
Now I have a secondary retention system.