Major singles titles and other standings--how it breaks down

I'm not usually one to get into a lot of numbers, but I've been thinking lately about the question: How many major singles titles can the WTA hold at one time? The answer, it turns out, is 55. Here's how it breaks down:

Serena Williams--23
Venus Wiliams--7
Maria Sharapova--5 (Wimbledon, AO, USO, 2 FO)
Angie Kerber--3 (AO, USO, Wimbledon)
Svetlana Kuznetsova--2 (USO, FO)
Vika Azarenka--2 (Australian)
Petra Kvitova--2 (Wimbledon)
Garbine Muguruza--2 (FO, Wimbledon)
Simona Halep--2 (FO, WImbledon)
Naomi Osaka--2 (USO, AO)
Sam Stosur--1 (USO)
Caroline Wozniacki--1 (AO)
Sloane Stephens--1 (USO)
Alona Ostapenko--1 (FO)
Ash Barty--1 (FO)

Soon there will be 56. Who will hold that 56th title?

Here is a list of women on the tour who have been singles runners-up at majors but have yet to win one:

Vera Zvonareva (Wimbledon)
Sara Errani (FO)
Sabine Lisicki (Wimbledon)
Genie Bouchard (Wimbledon)
Madison Keys (USO)
Karolina Pliskova (USO)
Marketa Vondrousova (FO)

Finally, here are the women on the tour who have won Olympic medals in singles:

Venus Williams (gold)
Vera Zvonareva (bronze)
Serena Williams (gold)
Maria Sharapova (silver)
Vika Azarenka (bronze)
Monica Puig (gold)
Angie Kerber (silver)
Petra Kvitova (bronze)