These large subgroups have their own pages:

• Stoves
• Cookware
• water

* Normal use can openers

• EZ-duz-it traditional opener - exceptionally well made
• side opener - while theoretically safer (no sharp edges on the opened can, they may be more useful when one wants to temporarily reclose the can after partial use. The can lid sits back in place on the cut sides.

* emergency use, practice before you need them

• the opener on a Swiss Army Knife (SAK), both the backwards-motion Wenger and forward-motion Victorinox style
• multitool opener, most are Wenger style AFAIK
• p-38 military style which can be carried flat in a wallet.

There are plenty of how-to vids on YT.