Check out Twist. https://twist.com

I have no affiliation with the company/team, but love the product so much that I want to share it here!

The whole idea behind Twist is to be a team communication that doesn't have the productivity issues Slack does. I think it's a very well positioned and timed product.

We've been using it for months at our startup, Canny. Threads are a useful level of organization, such that it's always easy to find what I'm looking for. However, I don't feel like I need to check it constantly.