And even more fan blades.  Black-plastic 4-bladed impeller, each measuring approx 4" across with a 3/16" bore. Designed for clockwise rotation. No motor. Just blades. (But nice little blades.)

This little black plastic fan and frame measures 2” square x 7/8” thick, and is a 12VDC 0.15 mA brushless model EFB0512HA. Has an air flow of 11.40cfm, and spins at 5500rpm. Able to operate from -10 to 70 degrees Celsius. Has a pair of 6” long red/black leads with a quick-disconnect.

Muffin fans, pay attention. You pick the "nice" 110 VAC 21W fan from Thermocool, measuring 4-3/4" square x 1-1/2" thick with an unwired offset two-pin power connector, rated for 82-95 cfm and spinning at approx 2600 rpm, with five blades and 3/16" mounting holes at the corners (Mfr part # G12038HA1ST); or the "beastly" 110VAC 36W muffin fan from the same mfr, which blows up to 198 cfm at 2900 rpm and measures 6-3/4" x 6" tall x 2" thick with (2) power terminals on a removable shroud, 5 blades, 5/32" mounting holes on the corners plus a ground lug. Both UL.

Come on sing it. Do you know the muffin fan, the muffin fan, the muffin fan… These are 12VDC 4-3/4” x 1” take out muffin fans. All working, all have short leads, some dusty and some not so dusty. School project? Perfect! Art student? Right in your budget! DIY’ER? Plenty to go around! Most are 9-blade, Cooler Master DC12V 0.3A model number FA12025M 12BPF but don’t be mad if they are a little different. No RPM specs but what do you want, they are true surplus.

Of course you’re not, but you might like squirrel-cage fans like we do. If so, this take-out, cream-colored ABS plastic squirrel-cage blade is for you. Originally from portable AC units, they measure 6-3/4" dia x 3-3/8" across with a flattened 5/16" ID bore and a 3/4" shaft that extends 7/8” into the cage. Could be re-rigged for a gerbil wheel. Made in USA.

This little L-shaped low-pressure piston-and-diaphragm air pump has a 7/32" OD inlet and an 11/32” OD x 9/32” ID outlet, and is attached to a Mabuchi RK-555PH 12VDC motor that draws 100mA no load, stalls at 4.3A, and spins approx 3500 RPM. Measures 4" x 1-5/8" x 3" with 2” leads.

This 12VDC low-pressure, piston-driven, diaphragm air pump has a 7/32" inlet. This bad boy is rated between 6-12 VDC with 12 VDC being nominal voltage , draws 1.3 amps at 12 VDC.  Overall size is  4" x 1-5/8" x 3" with solder tabs but some may have 10" leads. Shaft has a 1/2" dia cam to drive the piston. Motor is Mabuchi RK-555PH.