Your search for "Winged Sliver 4" revealed the following:
Winged Sliver (CMM) from Commander Masters, available at 401 Games Canada. Rarity: Common Finish: Normal Artist: Anthony S. Waters Card Text:All Slivers gain flying.
Winged Sliver - Surprise Slivers (Foil) (SLD) from Secret Lair Drop, available at 401 Games Canada. Rarity: Rare Finish: Foil Artist: Anthony S. Waters Card Text: Surprise SliversAll Sliver creatures have flying.