Folk / Trad

Rocker

Ah yes Planxty.  And Jimmy MacCarthy, Mary Bergin......

Stuckfast

I agree with what @gringopig says about Steeleye Span except that their second album is really good, especially 'Lovely on the Water'. And @blobb is right that Silly Wizard were fantastic, shame they had such a crap name.

On The Shore by Trees is a brilliant but neglected folk-rock album from 1970.

Almost anything by Shirley Collins is worth listening to but especially Anthems in Eden / Love, Death & the Lady / No Roses.

The Watersons were great, especially the Frost & Fire album.

Martin Carthy has done so much stuff that it's inevitably a bit patchy, but the Crown of Horn album is excellent.

Surprised no-one has mentioned Nic Jones, who along with Barry & Robin Dransfield is basically the template for about 50 percent of folk acts today.

Of contemporary folk acts I am a big fan of Alasdair Roberts. He's another who has done a huge variety of stuff, but his album of ballads called Too Long in This Condition is incredible.

gringopig

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thermionic

Pendevig, Calan, Delyth ac Angharad, Bob Delyn a’r Ebillion, albym newydd gan Ar Lôg!

thomasross20

Great thread - only just started listening to that John Smith video - brilliant. I love this sort of stuff.

blobb

One of my favourites, Bob Fox. Complete with obligatory folkie rambling introduction.

Beautiful song - Sally Wheatley.

https://www.youtube.com/watch?v=ROhJuVZJPLs

stuartryanmusic

For acoustic guitar as the focus try Tony McManus. Also, Lunasa are amazing at the trad instrumental Irish (and beyond) stuff 

Creed_Clicks

Jeff Lang. Alt folk. Great guitar player from Australia.

blobb

Ossian

https://www.youtube.com/watch?v=8i-NHurjBac

CountryDave

Loads of great suggestions.
Have you checked out the Transatlantic Sessions? Lots of different artists (including a number mentioned above).
Alister Atkin (of Atkin guitars) has a great cd ‘In time’ with Kathryn Williams and Tim Edey on a few tracks too. 

fob