The PCB will contain copper, of course, and probably some gold plating. The solder will be tin with 5% silver. The device lead frames may be tin-plated copper, or just tin, and some component leads may be iron. If there are connectors there may be brass (copper/zinc) or phosphor bronze (copper/tin) Inside the ICs there will be aluminum, possibly gold (though not on the silicon, they don’t play well together), and traces of other exotic metals.
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