This fan has driven by a tiny DC motor, which includes a high ratio gearbox.    A 3v power supply or two-AA battery pack can drive it.

The mechanism is a classic rotary to linear design, modified to oscillate the fan back and forth around a pivot point.  

The optional handle needs to be glued to the base.

The DC motor is from Amazon, Micro DC motor, gear speed reduction to 200 rpm, metal gears.  $6.99 (6/2025)