Integration of Slack with Zoho One happens how?

Integration of Slack with Zoho One happens how?

I'm seeing that there are 10 or so Zoho Apps for Slack but we're using Zoho One and aren't going to pay Slack for the upgrade necessary to add so many apps.  Is there not a single App between Slack and Zoho?  Must we use the CRM, and Books, and Projects, and, and, etc. Apps??