Thrift shops near me also. They have tons of audio equipment, old PCs, printers, etc. Not to mention less sophisticated things like toaster ovens and microwaves.
I think they have small cell phone power adapters, but nothing sophisticated.
I have no idea where everything ends up, but Best Buy usually has electronics recycling bins by the front doors of their stores. I seem to remember one specifically for cables and connectors.
One of the big computer service and repair chains in this area accepts obsolete gear from people. One weekend in February they hold a drive where you are encouraged to bring stuff in and they are prepared to accept the extra volume. However, they will accept reasonable amounts (no truckloads) at any time of the year.
If a computer has any capability at all in running reasonably recent software (no 186s) it will be refurbished and donated to a school. Totally obsolete computers and parts, and I imagine the cables, are scrapped for metal recovery. I even took the last of my CRT monitors to them.