#3 Asuka
Asuka was once the most dominant women's Superstars in WWE history.
Asuka was the longest-reigning NXT Women's Champion in history at 510 days and never lost the title before departing for the main roster. Upon her arrival, she continued her undefeated streak and was the inaugural winner of the WWE Women's Royal Rumble match. Overall, her undefeated streak made it to 914 victories, before losing to Charlotte Flair at WrestleMania 34.
A former WWE writer just went after JBL for his comments HERE
After a few months of back and forth booking for the remainder of 2018, Asuka would capture the WWE SmackDown Women's Championship at WWE TLC. The reign would go 100 days before she would lose the title to Charlotte on SmackDown. Ever since, Asuka has been in a go-nowhere tag team with Kairi Sane, the Kabuki Warriors. I don't think it is too late just yet for Asuka to reclaim her former position as the toughest women's Superstar in WWE, but to do so, she may have to return to NXT.
In NXT, the hardcore fan base that loved her so still remains, and are clamoring for a return and feud with current NXT Women's Champion Shayna Bazler. Asuka could very easily return, run through several women on the roster and reclaim what she once had.