This might just be the smallest brushless FPV quad out there. Its 46mm motorpost to motorpost, so in that measurement it loses to the Jellyfish but that one has prop guards and sits very tall in comparison. If you put them side by side mine would be smaller :) I literally just picked the name Yokto, because Betafpv used Pico, and IRC Ghost uses Zepto and Atto. Yokto is the smallest in that series anyway so why not (just dont think its an 8-rotor!)

This was just an experiment, to see how well a little stone would fly. It doesnt fly bad, but it isnt as impervious to wind as i hoped (I based my predictions on throwing a little stone - very little cross section so not much for the wind to catch). And its not particularly efficient, so I would probably just fly my mobula6 or Walksnail Whoop instead if i wanted to fly. But its cute AF and always generates conversations so in that sense, i am happy with it.
Edit: I forgot to add this, the number one question I get when people see the size of it:

Small doesnt necessarily mean light, and it was never intended to be the lightest whoop. It uses outdated 16mm separate FC/ESC/VTX, and a 3D printed frame. I actually wanted it to be huckable outside, so If you want the lightest whoop go see Angry Don's video he made about his 14g whoop.

But and it was silly cheap to build thanks to there being a lot of unwanted parts that are perfect for it. FC is an F3, but thats fine. ESC is actually a FishPepper clone that i found selling super cheap (Racerstar Star4 4A ESC was selling at SpeedyFPV for $5). The originals cant be found anywhere, but if you have one of those that would be the best. The VTX is a 25mw vtx i pulled off the back of a smashed AIO camera (Eachine EF-02).

Its a very fiddly build though, so i wouldnt try making it if you arent comfortable with small soldering and careful wire measurements to get everything to fit. "Can i use xxxx instead?" probably not - I have 0.5mm clearance on the props as it is. It may be possible to use a different VTX, if its thin enough, or use a different ELRS receiver, but the FC sits perfectly in the grooves under the frame, and the ESC is the smallest and lightest 16x16mm ESC available. Actually, there is an F4 version of this FC out there, but I havent seen that for sale anywhere. This should fit as well if you can find it.

Batteries are also a bit of a pain. Being this small, you want the smallest batteries available. 300mah cells stick out so far front and back its kinda silly. I fly it on 220mah Nekopunch batteries i got here in Japan, but they only give it 1:45-2 minute flights on these 26000kv motors... It does fly (suprisingly well) on this 530mAH GNB battery, but its really more battery than quad at that point.

Short and not particularly impressive video of it flying. More of a "Hey it flies" type proof... I think it needs tuning to handle propwash (and by extension, wind) better. But it tracks straight indoors and its "good enough" for most flying.