This Politico article sets out the rules for candidates to qualify for the first two Democratic presidential debates, and concludes that two individuals who have never held elective office may qualify. They are Andrew Yang and Marianne Williamson.
The rules require them to receive contributions from 65,000 individuals, including at least 200 individuals in each of twenty states. Or they may qualify by polling at least 1% in a national poll. But if these two alternative methods result in more than twenty candidates qualifying, then every candidate must meet both alternatives.
The article says Andrew Yang is closer to qualifying than Marianne Williamson. Yang’s webpage says he already has contributions from 56,000 individuals. See this wikipedia article about him. Thanks to Election Law Blog for the link.