I have recently read in older book (I don’t have it on me, it was from at least 90’s) about LC filter with resonance in chapter about filters in power supplies. It looks like regular pi LC filter but with additional capacitor parallel to inductor. Resonance frequency of additional capacitor and inductor was equal to frequency of rectified signal which give this filter good suppression of ripple voltage. It sounds great, but I never seen it used in any device, why?
Example of this filter: