Pretty much anything that is hard and not round can be used to pry off a bottle cap. I've probably used 100 different types of objects.
Usually a lighter or my belt buckle.
My preferred method is another bottle...
p38. vietnam issue from my dad.
I have used a piece of paper.
the edge of my desk...
A lighter is great, as well as the edge of something... (almost anything) that can grip a few "teeth" of the bottle cap as I smack my wrist with my other hand. There is not a lot that can keep me from my beer.
fold it in half repeatedly until you can't any more, then use the last bend point (Bottom of the U) like you would a lighter.