Brainteaser: build a bulk Gmail contact extractor, Zapier included

So I found some free bulk gmail extractors that work, but they all charge for the full versions.

With Zapier, it appears as though you can only use "received" mails as a trigger for Gmail-- this prevents me from copying existing information from emails in my inbox, because I can't trigger a "new" or "received" email from an email that I already have.

So, I'm left with a programming conundrum: I have all the tools I need, Knack, Zapier, Gmail...

there are even free scripts that exist.

I'm a bit lost on how I can hack this together:

1)copy any email address from any field from all existing inbox emails

2)input into spreadsheet

??? ideas?

I will post my solution later when I figure it out.