I’m a bit computer illiterate, but can I champion CALAN , and, if you like more traditional music, ALLAN YN Y FAN?
If you enjoy traditional folk music and an play an instrument, there are a number of “tune clubs” where you can learn, and play, Welsh music. Of the top of my head, there’s one at Llancaiach Fawr, Old Tredegar, Merthyr, Blaenavon, Llanfoist…
The Llanfoist group has members from various groups across South East Wales, and as Gwerin Gwent, will be doing 2 sets at St Fagans on Saturday.
Yes you can. For people unfamiliar with these groups, here are a couple of tunes:
I have previously heard quite a lot of their music and have always enjoyed it. They are very talented and dance well too. I would probably think of them as modern folk and Kân is one of my favourites. Thanks to @robbruce for posting it 
The fabulous Kizzy Crawford’s latest release. Hope you enjoy it. I think @margaretnock will like it too.
Kizzy Crawford Music shared: 
I’ll be at #cheltjazzfest with my band in May - so excited! Tickets are now on sale: http://bit.ly/2RIQSyA
Steve Eaves
I was lucky enough to hear this very talented singer a couple of times last year in Caernarfon. I think she’s finally working towards releasing an album. I bought a hand produced E.P. from her which is excellent. A very lovely young lady too. 
Her 2 E.P.s are available here if you like her.
Beautiful voice! Thank you for sharing.
I’d really recommend seeing Al Lewis live if you get the chance, I thought he was ok, then saw him at Clwb Canol Dre a couple of weeks ago, the guy is mesmerising, a true talented professional, and pitch perfect, what a voice, what a performance!
Edited to add - No idea why that particular video won’t embed.
Even when I copy and paste is says “Video unavailable”. I don’t know if it is protected.
Weird. I went back to the video and the privacy setting was set to Draft, which I didn’t know was even an option. I’ve set it to Public now, but it still won’t embed. 
Edited to add: Oh. Look.
I agree, great talent! I like most of his music. He has quite a lot on YouTube complete with lyrics