Food
If you can't find your bottle opener, using a metal key can also help you enjoy your cold beer. Keep it under the cap and poke to loosen it.
Yes, paper can also be used to open the cap. Just make sure it is a thick piece of paper, folded multiple times to make it strong enough to lift up the cap.
Metal scissors can also work in an emergency. Place the top arm on the top of the cap and second one below to open it.
If you cannot find anything, just place the bottle near the countertop with the cap's grooves resting on the table and smack in the downward motion.
Your ring can also be used to open the cap. Place your ring finger below the cap and exert pressure to crack open your beer.