According to wikipedia, VA Governor Terry McAullife-D has publicly expressed interest in a

[MyMission]

58. many names to watch over the next few years

Jason Kandler was mentioned during the DNC election.
Pete buttigieg was impressive, but will still be under 40 in 2020.
Jaime Harrison, another DNC chair candidate will be in his 40's, as will
Sally Boynton-Brown.
Who knows, Ellison or Perez, both in their 50's,could emerge as a potential candidates, but neither appears to be the best option at the moment.
As for women, Elizabeth Warren is amazing, but (forgive me) too old.
Kirsten Gillibrand,Kamala Greene, and Tammy Duckworth are 3 women who impress me.
There are many others, and time will tell. I just hope that the democratic powers that be will be open to a relative newcomer.