Reciprocating fluid pumps include a plunger configured to expand and compress in a reciprocating action to pump fluid, and one or more magnets carried by the plunger. The one or more magnets may be used to impart a force on the plunger when the plunger expands and compresses in the reciprocating action within a pump body responsive to a magnetic field. Shuttle valves for shifting flow of pressurized fluid between at least two conduits include a spool movable within a valve body and one or more magnets carried by the spool. The one or more magnets may be used to impart a force on the spool responsive to a magnetic field. Reciprocating fluid pumps may include such shuttle valves. Methods include forming and using such pumps and shuttle valves.