Quote from VegaTDM »Can you cite a rules document either way? A judge on the channel literally just told me that they are considered magic cards since the official rules state nothing about the color of a cards border whatsoever, and would not be allowed in the deck box regardless of the color of their border since they are neither cards on the decklist, nor tokens.
There is nothing in the comp rules, though the following does appear in the MTR under authorized cards
Quote from• The card is genuine and published by Wizards of the Coast
• The card has a standard Magic back or is a double-faced card.
• The card does not have squared corners.
• The card has black or white borders.
• The card is not a token card.
• The card is not damaged or modified in a way that might make it marked.
• The card is otherwise legal for the tournament as defined by the format
As Noobincube has stated UnCards have a silver border so are not elligible for use in a sanctioned tournament so should be ignored if they are extra in a deck box