We use small or big fans for all sort of things: from cooling the stepper driver, motors, hotend, or the printed plastic itself...
They are easily salvaged from old computer but here is some, with their suppliers and specs to compare. You are welcome to complete the blanks if you know missing information.
|Vendor||From||30 mm||40 mm||50 mm||Additional notes|
|Think3dPrint3d||UK||40mm fan||Various connector types. Ships worldwide.|
|Alfa-Tech3D||DK||30mm fan 12V||40mm fan 12V||50mm fan 12V||All Fan with Ball Bearing, 5V, 12V and 24V, Delivered Worldwide.|
|Aus3D||AU||30mm fan||40mm fan||50mm fan||Also other types (blower fan, etc). Ship worldwide.|
|UltiBots LLC||USA||12v & 24v||12v & 24v||100cm lead wires NO solder/crimping - Blowers ALSO...|
|Threed||MX||30x10mm fan||40x10mm fan|