Solo singer-wise there's some great material to be found with current singers like Chris Wood or Nick Hart. And if you go back a bit there's some really interesting songs from people like Tony Hall (lots of Norfolk oddities) and Dick Gaughan (Scotland. Kist O' Gold is a great album).
I tend to know more about tune history than songs but songs do give you a lot of scope for reviving old music. I know Faustus, for example, take old lyrics and write new tunes for them to change the sound. It's a really exciting way of keeping the stories alive and maintaining their relevance for new generations.