…hat other artists would tickle my fancy?
Willie Dixon, definitely. 
Howlin’ Wolf.
Son House, perhaps.
I like many blues artists, including Muddy. But in my view, when it comes to blues, there’s Howlin’ Wolf…and then there’s everybody else.
I would start with Wolf.
That’s how I feel about it. They’re great contrasts, similar enough that most fans of one will like the other but different in some fundamental ways. For my money, Wolf is the best singer there ever was.
I think it depends on what recordings of Muddy Waters you like and what it is you like about them. But you can’t go wrong with Robert Johnson.
Looking in one direction, Son House, Willie Brown and Charley Patton were three big names in Mississippi when Muddy was coming up, and Big Bill Broonzy gave Muddy a big helping hand in Chicago.
Looking in the other direction, Johnny Winter and Bob Margolin are closely associated with Muddy, but there are many more.
For a slightly different kind of Mississippi blues, check out R.L. Burnside and others.
None of the aforementioned are exactly like Muddy.
Little Walter (Jacobs) and Otis Spann were both in Muddy’s early bands; the music is very similar (and Muddy guests on a lot of their material).
Buddy Guy is one I’d add. Of the ones the others have mentioned, especially Howlin Wolf. Not the same thing at all, but the same kind of commitment.
I’ll second everyone mentioned before, and relish that I get to be the first to mention John Lee Hooker 
ETA: So good I had to listen to it twice.
Don’t forget Elmore James.
D’oh! I really should have mentioned Hooker too, as he’s second in line for me behind Wolf. And if anything, for the OP’s purposes he’s somewhat closer stylistically to Muddy than Wolf is.
But really, he’s an entity unto himself. Start with his earliest sides recorded up in Detroit, and then move forward from there.