(60 mm, XR-1) - 60 mm PC fan with silent wings - PC case fan - Maximum volume is only 11 dB (A)

Noiseblocker XR1 BlackSilentFan Series Tower Fan 60 mm

AABCOOLING Super Silent Fan 6 - Silent and Efficient 60mm Fan with 4 Anti-vibration Pads, PC Fan, Mini Fan, 12V Fan, 3D Printer Accessories 17.3 dB(A), 2500 RPM, 20 CFM

Noctua NF-A6x25 FLX, Premium Quiet Fan, 3-Pin (60mm, Brown)