How to search the world?

The world outside my doorstep is unorganized chaos and I am blind to most of its existence.

Say I'm looking for a job. And I know what job I want to do. I can search for it on a job listing site, but there will still be many such jobs that won't be cataloged on the site and that I'll hence be missing. How can I find the rest? What are some alternative approaches?

Also there are two ways you can end up with a job: either you find it (going on a job search), or it finds you (headhunters etc.). Obviously the latter possibility is much better as it's less tiring and it means you end up with an over-abundance of opportunities (if people message you every week). What are some rules of thumb for life to make it so that the opportunities come to you? (and not only for jobs)

Often I don't even know what opportunities are on offer out in that misty unknown (and my ADHD brain finds it straining to research them (searching 1 job site feels almost futile because you don't know how many of the actual opportunities you aren't seeing)), so the strategy I resort to is imagining what I concievably expect to be out there and then trying to find it. This has several weaknesses: firstly I could be imagining something that doesn't actually exist and waste hours beating myself up because I can't find it. Or, almost even worse, my limited imagination might be limiting what sorts of opportunities I look for which means I miss out of the truly crazy things out there.

Here's an example of an alternative approach that worked for me once:

Last month I wanted to visit a university in another city for a few days to see if I liked it, and I needed a place to stay. I first tried the obvious approach of searching AirBnB for rents I could afford, but none came up. Hence I had to search through the unmapped. What ended up working was: I messaged the students union -> they added me to their whatsapp group -> sb from my country replied to my post on there adding me to a different WA group for students from my country -> sb in that WA group then DM'd saying I could crash on their couch.

I would have never thought of trying an approach like this when I set out, and yet I must have done something right because it worked. What? The idea to message the students union and join whatsapp groups took quite a lot of straining the creative part of my brain, so I'm wondering whether the approach I took here can somehow be generalized so that I can use it in the future.

TL;DR: Search engines don't map the world comprehensively. You might not even be searching for the right thing. What are some other good ways to search among the unstructured unknown that is out there?