John Barleycorn is a solid contender.
These are a few of my favs
Silkie
https://www.youtube.com/watch?v=6zZy2Q3QY0Q
https://lyricsjonk.com/joan-baez-silkie.html
False Knight on the Road
https://mainlynorfolk.info/steeleye.span/songs/falseknightontheroad.html
https://www.youtube.com/watch?v=OEpBlbSWmh4
The Trees They do grow high
https://www.lyrics.com/lyric/964557/Pentangle/The+Trees+They+Do+Grow+High
https://www.youtube.com/watch?v=LU3Xeo0kabc
Christy Moore “Well Below The Valley”
https://lyricsjonk.com/christy-moore-the-well.html
https://www.youtube.com/watch?v=-mjWhMn-VnU
mmmm Well Below the Valley, dark. Also if you havent heard the vetsion by Omnia (theyre weird Erf freaks) give it a go.