as an avid lover of keychain trinkets, i think flashlights are the most essential one of them all. if you're gonna have one thing other than your keys, consider a tiny flashlight. you'll appreciate having it when you need it.
pictured is the olight i1R 2 EOS. it's rechargeable via micro USB, which is outdated, but i like how small it is, since keys can get bulky real quick.
if USB-C is a must, there's the olight i1R 2 pro, which is a little bigger in comparison.
