How do you actually find roles that never get publicly posted?

I've spent the past few weeks digging into how people land jobs that never make it to a job board — trying to separate the tactics that actually work from the recycled "80% of jobs are hidden" stat that gets repeated a lot without much evidence behind it.

For those who've actually done it: what worked? A referral, a cold email straight to the hiring manager, a tip from someone inside? Trying to figure out which of these still hold up in 2026 versus outdated advice.