Yes It's possible. Some of these lead gen companies (pretty big/serious companies) actually.. They share data on revshare, with publishers if you can do a certain amount of volume for them of course. Ofc you need to proof that you can actually deliver, before they even consider talking to you.
Rev share data from 3rd party companies - what do you mean by that?
All networks work on rev-share, otherwise how would they make money
You wanna search for companies, that typically provide insurance, casinos, telemarketing and ngos leads.. A little google goes a long way.
Maybe queries like co sponsor, co registration and co promotion.