Few years back, for my birthday, daughter gave me a magnet broom; similar to this, but only a foot wide and no wheels.
I have no idea how many small parts this thing has found after they were dropped/sprung away/otherwise left the table and vanished on the floor. It just found a trigger rebound slide spring that I had taken to the garage and rolled off the bench.
A very handy thing. If you work on stuff and don't have one, you might consider getting something like it.