HamSCI
Radio Astronomy (DM2) (google.com)

ELF
VLF Natural Radio Experiments – Zach Poff
Explorer E202 - VLF portable receiver

Spherics
Spherics and Tweeks (uni-kiel.de)

Ionospheric doppler
Waterfalls from the December 2021 eclipse frequency measurement – Daniel Estévez (destevez.net)

Sudden ionospheric disturbances
SIDs - Radio Astronomy (DM2) (google.com)

Meteors on VLF
Meteors & VLF - Radio Astronomy (DM2) (google.com)

Ionospheric intermodulation
Sideband Asymmetry in Ionospheric Cross Modulation - Boer - 2018 - Radio Science - Wiley Online Library