this zoomie Review: #3 Noname $3.60 XPE-Q5 single AA/14500 zoomie
They can be had cheaper on aliexpress, search ‘XPE flashlight’… but those are 3-mode.
The problem with 1x/2x AA lights is that they all necessarily use booster circuits (at least with modern LEDs). The main advantage of this format/battery type is size/weight, not power.