For people in the UK, Prospect has a Tech Workers branch: https://prospect.org.uk/tech-workers/
Prospect is my union (although I'm a member of a BECTU branch rather than the Tech Workers branch as I work in the broadcasting industry) and it's well worth the dues I pay.
I should note I’m US based.
This is great, thanks for sharing. Something like this could be a good resource for folks like me looking for prior art.
In recent decades unions have been demonized. And I understand some of the criticism, but IMO now is the time to get something organized for tech. The alternative is just to sleepwalk into the unemployment line