""If 'Little Boxes' and 'The Red Flag' are folk songs. we need a new term to describe 'The Outlandish Knight'. Searching for Lambs' and 'The Coal-owner and the Pitman's Wife'."

I see little in common between any two of those five songs, beyond the fact that all five have appealed to, and been sung by, lots of people.

They are of five different vintages.

'Little Boxes' and 'The Red Flag' are both political (in different ways), but so is 'The Coal-owner and the Pitman's Wife'. The latter two both concern the "class struggle".

'The Outlandish Knight' and Searching for Lambs' both concern courtship, but under drastically different circumstances.

As for the quality of the poetry: I'd put 'The Coal-owner and the Pitman's Wife' well ahead of the other four, but that's a personal opinion.

Jim, what attribute do you see as being clearly shared by your last three but neither of your first two?