From a developer point of view one frequent advise is to never give a number first.

https://www.kalzumeus.com/2012/01/23/salary-negotiation/ has a chapter on that.

Are there companies who provide this?

Yes, well, consultants and ebook writers. Most seem to target freelancers who want to raise their prices though, not job starters. For example https://doubleyourfreelancing.com/