Re: Best players to never reach a slam final?
Manuela Maleeva, definitely. She is the only candidate to consistently rank in the top 10 during her career and just never break through at the Slams. Claudia Kohde-Kilsch, her contemporary, is close, but was consistently ranked below her and didn't stay at the same level later in her career. Amanda Coetzer really only had one big breakthrough year where she pushed to #3, but spent almost her entire career outside the top ten.
Two earlier players who deserve mentioning are Annette VanZyl DuPlooy of South Africa and Julie Heldman. VanZyl was close to the top 5 in the mid to late 60's and made 3 Slam semis, but like many of her countrywomen got married and didn't play as regularly afterward. Heldman also made 3 Slam semis and was #5 in the world. She had several years in which she only played part-time and so she is in and out of top ten lists. She was probably a bigger threat to those above her than any of the players mentioned in this thread and had wins over Court, King, Richey among others. Richey mentioned her and Ann Jones as her most difficult opponents to play.