I had a couple of standard size servos in which i had stripped the plastic gears, relatively useless as there isnt a good way of getting the spinny out of them.
So i took them apart and turned them into 5v ESCs.
First one opens them up, finds the center for the potentiometer which will stop the servo spinning all the time, its the same mod as making one a 360 servo essentially.

Then i unsoldered the servo motor and replaced it with two leads that are easy to connect to something else.

And just a bit of heat shrink to finish up.

They wont have huge amounts of amps to give, supposedly 2.5A for these MG996R servos but im pretty sure these are knock offs since they didnt actually have metal gears, just the last gear was brass or something, the plastic second to last stripped in no time, so id expect the electronics to be knock off quality too.
Anyways, recycling and possibly useful for something, they turn the yellow 1:48 gearbox motors im intending to run in my my PZ2 fine, will see if they are fast/strong enough when i get it to a driveable state.
If not then they might be alright for small motors doing turret turning or gun elevation.