There are 10 Mary Long trading cards tracked on HobbyCardIndex, spanning Soccer. The most valuable is the Mary Long #GRS-ML at $91.13 raw.

Source: HobbyCardIndex · Updated daily · https://hobbycardindex.com/players/mary-long

Mary Long Cards

Name: Mary Long Card Price Index — Historical Data
Creator: HobbyCardIndex
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10 cards · Soccer

All Mary Long Cards