Duke Ellington, followed by a long line of other great Jazz players who I'll leave to other 'Goners to name.
Toussaint is a nice get for (pop/rock and) blues as would be Professor Longhair, to whom all of the N'awlins piano guys own a debt. That Barrelhouse to Blues to Rock lineage really fascinates me and Prof is a (probably the) main man in that process. A lesser known player worth seeking out in this style is James Booker. Another obscure name from early on is Cow Cow Davenport. Jelly Roll Morton is also worth checking out and Fats Domino is fun at the back end of the process. Dr. John is.....well, there are so, so many more, I'm sure you'll love the search.
Good Luck.
Marty