Use a third-party service like callrail or calltrackingmetrics. There are many competitors to those two as well to pick from. Source: about 3 years ago

Integrate everything! There’s over 2500 integrations already available in the app directory: https://slack.com/apps. Source: almost 2 years ago

The Slack Google Calendar app is the third most popular app of the 2,400+ native integrations in their directory. It allows you to take basic actions for your Google Calendar events right in Slack, and simplifies managing your daily schedule so you can reallocate the wasted time switching between apps towards more high-value work. - Source: dev.to / about 2 years ago

You can always try developing your own plugins for slack or discord, maybe there’s already something for you: https://slack.com/apps https://betterdiscord.app/plugins. - Source: Hacker News / over 2 years ago

The Slack app directory is a mega-database of hundreds of integrations available to enhance collaboration and productivity for small teams up to entire enterprise organizations. These apps allow you to work simultaneously across tools to push and pull information, enhance each tool's functionality, increase adoption, and streamline communication asynchronously right from where you're already working and... - Source: dev.to / almost 3 years ago

Want to get something fancier than Slack’s native capabilities for your productivity needs? Head off to Slack’s official app directory, and pick something nifty to fit your needs! - Source: dev.to / about 3 years ago