Keep in mind I'm just throwing these out there
Paul Tsongas: I think he was mentioned as a possibility. Could balance the ticket geographically and make it seem more grounded.
John Silber- President of Boston University and 1990 Democratic nominee for Governor of Massachusetts. Suggested by the Boston Globe
Dr. Bernadine Healy: Head of the National Institutes of Health, former professor at Johns Hopkins. Perot tried to recruit her but failed.
Ralph Nader: used as a write-in candidate in New Hampshire, already well known as a consumer advocate
John Hagelin: Just started the Natural Law Party, beliefs might be popular in liberal California and east coast.
Joe Walsh: the musician not the veteran hating ahole from Illinois. He did run for Vice President!