If you find one of those then let me know. I don't believe they exist.
Bernie Sanders has never accepted a corporate check in his 30+ year long career in politics. That's basically his thing. It's what he has been fighting for all his life.
He has an extensive list of personal donors instead, which the corporate democrats tried to get from him.
There's a group called Justice Democrats that are gaining traction. Their one single requirement is: Do not take corporate or pac money. https://justicedemocrats.com/
They have a few members in congress already, iirc.