Yeah, that bugs me beyond belief, “What’s THE perfect light I should get?”.
Like, if there even were one, we’d all have it…
Oy! That’s moine! 
Ironically, headlamps are among my least-used, despite probably needing to use 'em more often, and having a half-dozen that were hanging on various doorknobs for ready access, only to be charged then put… somewhere.
Like just an hour ago, if that, I had to clean out the litterboxes for garbage-collection tomorrow, and could’ve used one. My motion-activated lamps stay on like 10sec, and I gotta wave like an idiot to retrigger them. So I got my… oh, what was that first touch-activated lamp that I think Gearbest had? Zanflare… T1? L1? Whatever.
Love that little bugger, stuck it to the fixture (magnetic), and used that for light. Headlamp would’ve been so much easier.
You make a distinction between that and an AAA light, but I’d keep an AAA twisty (secured with scotchtape so it doesn’t twist/untwist accidentally). Otherwise, my “keychain light” is the light-up key-blank I got.
https://www.amazon.com/dp/B000LNWVY4/
Dunno if this is the exact one I got, but it’s close enough.
MH20. Can’t get any more compact than that, with sideswitch and usb charging.
Mmm, can’t really go wrong with C8s. Also the Catapult Mini for small, IF22A for more oomf, and so on.
As long as you got something with more capacity Just In Case, yep. TS10, GTmicro, etc., are all great compact lights, but the 14500 is an anaemic cell, all things considered.
Nice cheap lightweights like the infamous Glaree AAA twisty. the Skilhunt series (incredible value for the price!), and others. I tend towards twisties, because a discrete switch like on the Tools lengthens the light to the point you might as well just go to an AA/14500 light line an SP10.