Convoy tiny (SS)
Olight I3E Eos
Jetbeam Jet-U
Maglite Solitaire
I have the above 4 single AAA lights and like them all for completely different reasons, but my Nitecore Tip SS is on my keyring for the foreseeable future, awesome light.
The Jetbeam Jet-U is the best single AAA of the bunch. I have an Astrolux Copper A-01 on the way as well for further comparison.
For the last couple of years, my keychain flashlight of choice has been my Olight silver 120 lumen i3E EOS. I like that it’s one mode, and the silver (probably chrome) finish has been almost scratch free even though it’s been rubbing up against keys all the time I’ve owned it.
The UltraTac K18 has been my go to keychain/pocket clip edc for quite a while now. Ended up with 2 of them, because they are fantastic either with a AAA or a 10440.
Lovin’ my Nitecore TIP 2017 (i put a 219C in it).
Also love my Astrolux M01 (after fixing the flickering problem: replaced the e-switch thingy with a tiny piece of sheet metal…) which is a true keychain light, it’s on my key ring.
I have a Wuben G337 on my keychain I got for ~$10. I don’t use it that much, because I usually have a UT01, or a SP10b on me, too. But it’s there when/if I need it. Runtime and brightness are both impressive for something so tiny, and I can charge it from any micrUSB cord.
I’m pretty sure it shares the same charging circuit and 2 level resistor ballasted “driver” as many of the other similar tiny lights.
I got a couple of these Glaree E03 150 lumen AAA lights a few months ago on amazon, they are $7, sometimes on sale for $5, 3 modes + a strobe, pretty good light for the price