Your search for "Sentinel Sliver 30/249" revealed the following:
Sentinel Sliver - Art Series (Gold-Stamped Signature) (ACMM) from Commander Masters Art Series, available at 401 Games Canada. Rarity: Common Finish: Normal Artist: Lucas Graciano
Sentinel Sliver (Foil) (M14) from Magic 2014, available at 401 Games Canada. Rarity: Common Finish: Foil Artist: Maciej Kuciara Card Text:Sliver creatures you control have vigilance. (Attacking doesn't cause them to tap.)