There's a lovely manifesto on the 37signals (ex-Basecamp) website.
They have the controversial "no-politics" rule mentioned, but that doesn't make the rest of the 36 lesser.
Follow
My take on political discussions in work-related channels:
Write them if you absolutely must, but always add a content warning, so people who don't want to subscribe to your politics don't have to read them.
Slack tip: open a new thread with the message "CW: <topic>" and then add your thoughts as replies to that thread.
@nikoheikkila That doesn't solve the problem of marking certain opinions as "political" while other, "approved" ones can be discussed freely.
"Politics" is anything you don't agree with.