For whatever reason, sometimes I am only able to find one card of certain players. To be considered a One-Card Wonder, a player must have been active since 1991 (when I started paying attention).
The only card I own of Esteban Beltre is 1997 Pacific Crown Collection. Beltre played in 27 games as a backup middle infielder in 1996, hitting .258/.299/.290/.589 with six runs batted in and one stolen base. Beltre played 13 games at third base, eight at second base, six at shortstop, and one at designated hitter. He was not a particularly good defensive player and a complete zero with the bat, so it was not surprising that he was not brought back the next year.