LED keychain flashlights are a dime a dozen, but the Abitax 0510 Tag Light is a noteworthy example for a couple of reasons.  First, it’s confoundingly small and light so you’ll hardly notice it on your keychain.  Second, it’s brighter than MIT post-doc on fire.  The beam shines through the front and the sides of the housing so it provides a wide cone of light.  It was designed by Kazuma Yamaguchi so the look is functionally minimalist.  They are a bit hard to find in stores, but they can be purchased direct or through select online retailers.