Weasel away. There’s no question that Charlie Patton was vitally important. If we stretch my earlier metaphor, making Robert Johnson the headwater of the blues, then perhaps we can consider Patton the spring that feeds it. I declined to accord him primacy of place in my list on the grounds that the recordings that exist are so few and so damaged that it’s tough for anyone who’s not already pretty well steeped in the blues to understand why he’s so crucial.
Just about every blues artist I would recommend has been mentioned already. The only thing left is to suggest that you could look into the old school R&B:
Big Joe Turner
Wynonie “Blues” Harris
The Drifters (pre-Ben E. King)
The Ink Spots
Hank Ballard & the Midnighters
If you can get your hands on some of the early Ike Turner stuff that should be worth a try.
Howlin Wolf is reckoned to be the influence of many of the heavy rock groups such as Led Zepp and folk such as Eric Clapton and Jeff Beck.
Leadbelly IIRC was well known to the Seeger family but his influence is not that obvious.
Folk music is far harder because it was exactly that before the mass media really got a hold of music. It was stuff that ordinary folk would sing to enertain each other.
The folk music we think of today - often socially aware and about the human condition is close in its way to the kind of place blues came from.
Good examples would probably have to include country music or immigrant music from the Irish, and the Scots.
On that basis try,
of the English folk then
if you want a musician who is true to the tradition of the travelling artist type then you must check out
He plays the Mandolin but it is probably closer to old folk musicianship than anyone out there.
He plays sea-shanties which are a huge part of sailing history, local reels, and shindigs.
He makes it sound easy but in his hands the instrument sings he really is a rare talent.
In fact his standards are so high that other musicians in the folk field queue up to play on his recordings.
It is fair to say that he has helped in part to renew interest in the older folk music tradition.