Dialog Messenger - handy and feature-rich enterprise multi-device messenger available for server or cloud – Slack-like, but not Slack-limited
Lurchr - Saves all your Slack links, so you can focus on work
Ripcord - A desktop chat client for Discord and Slack
Discord → Slack - A free tool for migrating your data from Discord to Slack
Done Hui - No need to switch between multiple pieces of software to get through the workday. CHATS: Communicate freely. CALENDAR: Know your team's availability, plan meetings. No more conflicts. TO-DOs: Stay on top of all projects. FILES: All files, one spot.
Slinky - Your slack links — organized!