Your search for "Excavation Technique 16" revealed the following:
Excavation Technique (C21) from Commander 2021, available at 401 Games Canada. Rarity: Rare Finish: Normal Artist: Francisco Miyara Card Text:Demonstrate (When you cast this spell, you may copy it. If you do, choose an opponent to also copy it. Players...
Excavation Technique - C21 Reprint (PLST) from The List, available at 401 Games Canada. Rarity: Rare Finish: Normal Artist: Francisco Miyara Card Text:Demonstrate (When you cast this spell, you may copy it. If you do, choose an opponent to also...