Never found anything valuable - plenty of tennis balls, frisbees, footballs etc. Once found a kid's microscooter in a beech hedge. It had obviously been thrown on top of the hedge a year or two earlier, as it was rusted-up and well and truly "grown in". Left it on the pavement, was gone within an hour.
my old neighbour found a pair of Felco snips in a compost bin i had built on an allotment i used to have.....my work chum had lost them several years beforehand! He sharpened and greased them up and got to keep them!!