There are too many brands and sizes to cover them all here, so I picked my favorite ones (which I use and have tested through the years)
|Elite 799 air pump
Small pump with good lungs :) perfect for a beginner's needs. Can take up to 3 spawning tanks, maybe more.
|Elite 802 air pump
Quiet and powerful about twice more air output than the 799.
|Elite Optima air pump
BIG daddy of the Elite line, I love this one and
have 15 spawning tanks hooked up to it. Could hook up more. It is super
quiet, has a big knob to control air flow. I highly recommend it. Comes
with spare diaphragm :).