Well, tons actually, Greg. Frank Hennessy plays a good selection on his Celtic Heartbeat programme on Radio Wales (Sat nights, and "Listen Again" via the internet). There's a good 'sampler', Rough Guide to Wales, which covers everything from the 'archive' to modern groups. Arfon Gwilym brought out a CD of song a couple of years back (unfortunately from my point of view, we have more instrumental than song these days) and there are groups like Carreg Llafar that are worth listening to. Tons of instrumental stuff: Mabon, KilBride Bros., Crasdant, Never Mind the Bocs, etc. I think the great "Hwntws" from the 70s are looking to 'relaunch'. Again, the list on the trac website gives a good start ...

You mention Phil Tanner; it's a pity that St Fagan's Folk Museum has problems in publishing stuff in there collection. There's at least one singer who recorded a lot more than PT (but in Welsh mostly) but there are copyright 'issues'. We're working on the problem so maybe that will be sorted eventually.

There are a couple of good recordings of Archive material of course. The Plygain carols and the Stable Loft Songs have been re-released on one CD by Sain.

And there are, of course, a lot of books of both songs and tunes readily available for those who don't necessarily want to learn from recordings ...
siân