Your search for "Gustcloak Sentinel 12" revealed the following:
Gustcloak Sentinel (DDL) from Duel Decks: Heroes vs. Monsters, available at 401 Games Canada. Rarity: Uncommon Finish: Normal Artist: Mark Zug Card Text:Whenever Gustcloak Sentinel becomes blocked, you may untap it and remove it from combat.
Gustcloak Sentinel (Foil) (ONS) from Onslaught, available at 401 Games Canada. Rarity: Uncommon Finish: Foil Artist: Mark Zug Card Text:Whenever Gustcloak Sentinel becomes blocked, you may untap it and remove it from combat.
Gustcloak Sentinel (ONS) from Onslaught, available at 401 Games Canada. Rarity: Uncommon Finish: Normal Artist: Mark Zug Card Text:Whenever Gustcloak Sentinel becomes blocked, you may untap it and remove it from combat.
Gustcloak Sentinel (DDO) from Duel Decks: Elspeth vs. Kiora, available at 401 Games Canada. Rarity: Uncommon Finish: Normal Artist: Mark Zug Card Text:Whenever Gustcloak Sentinel becomes blocked, you may untap it and remove it from combat.