I tested RPM notch filter in Betaflight 4.0. It is awesome.

At the moment of publishing this video only some F4 and F7 flight controllers support RPM notch filter. A BLHeli32 ESC is also required, and it needs to be flashed with experimental firmware that enables bidirectional DShot support. And of course you need the latest development build of Betaflight 4.0.
(Pretty scarce) instructions in Betaflight Wiki: github.com/bet...
Great explanation and setup instructions on UAV Tech channel (shout-out to Mark): • Betaflight RPM Notch F...
Noise plots from the video in full resolution: imgur.com/a/b4...
Black box logs used in the video: drive.google.c...
~~ Check out my quad build logs ~~
Rotorbuilds: rotorbuilds.co...
~~ Download my 3D designs ~~
Thingiverse: www.thingivers...
~~ Quad in the video ~~
Frame: HyperLite FlosStyle 5"
Flight controller: Matek F405-OSD
Firmware: Betaflight 4.0 (dev version)
ESC: Aikon AK32 4-in-1 35A
Motors: Hyperlite 2207.5 2522 KV Team Edition
Propellers: T-Motor T5143
Receiver: FrSky R-XSR
FPV camera: RunCam Micro Eagle
VTX: FuriousFPV Stealth Long Range
Batteries: Tattu 4S 1300 mAh 75C
HD camera: GoPro HERO5 Session
AUW: 587 grams