Chip and Charger examples; Paul Annacone & Pam Shriver. Neither had much a baseline game, so they came in on everything.
Serve/Volley; there are many in this catagory, Becker (though he fancied him self a basline basher at times and it go him in trouble) & Tim Mayotte are two more.
As for the Baseliners there are too many to count.
I would use Micheal Chang as a baseline retriever, but wanted to be more a counter puncher. Miloslav Mecir was also a retriever.
Were would you catagorize Kimiko Date? She was something of a retriever, but hit flat pinpoint winners that constantly surprized her opponents.