Is there any website that provides a list of all the applied dominants in each of the major and minor scales?
Not that I know of off the top of my head. I am sure if you google around you can find one. The Music Composition 101 workbook lays out all the dominant 7th chords in each key though.
I meant secondary dominants like V/V etc. I’m having trouble trying to figure out what key would those be in.