Cruel Sister
Cruel Mother
The Elfin Knight (this is a tricky one, unless you read into it all the obscure sexual innuendo going on between the elf and the maid)
Suil a Run
Sheath and Knife (I'm most familliar with version 2)
Edward
Silver Dagger
Bruton Town
Hangman
Claudy Banks or Shores of Waterloo and all the hybrids
Tam Lin (my favorite is the Anne Briggs version)
Fair Margaret and Sweet William
The Digital Tradition is an awesome place to find the lyrics to these songs!