#1 Trish Stratus
Was there any doubt about this one? Between her in-ring skill, presence on the microphone, and looks, Trish is viewed by many as the greatest female talent in WWE history. She had a big retirement match in 2006 and has only been back a handful of times since.
If Trish were to enter the Women's Rumble, there would be a lot of dream interactions such as Charlotte, Sasha Banks, and Asuka. On top of that, WWE would be able to continue to go down the path of portraying Mandy Rose as a young Trish Stratus.
It has been almost seven years since Trish last wrestled a match in WWE. Being seen as the one who carried the women's division in the 2000's, it seems like an absolute must for Trish to be in this match.