Oh, my, the memories!!! I suppose I should be embarrassed that I remember so many of them, but most were heard (and loved) when I was a child and so are now fond nostalgia and secret sing-alongs.

And I agree about where's the original Purple People Eater? Perhaps a copyright problem?

The only style that "appears" to be missing is the pseudo bawdy song. The kind where you are positive that the last word in a verse will be naughty, except the refrain sweeps you in a different direction. The most recent one I've encountered is Hey Nonny Nonny by The Poxy Boggards.