This Greenstuff World mini airbrush compressor has been a great portable companion to my hobby, allowing me to spray on the go, at the FLGS, maker space, and so on.
It's not the only one of its kind, and is probably in fact just a branded version of all the cheap compressors you can find on Amazon, but this is the one I have!
Along with the compressor, I bought their cheap airbrush as it has a wide 0.5mm nozzle which is ideal for spraying goopy stuff like primer.
If, like me, you live in a cold place, and you need to paint your 3d prints and tabletop miniatures, check it out.
Portable airbrush compressors at Amazon:
Airbrush cleaning kit: