Native Discord client
Desktop client for the chat platform Cabal
Elegant Facebook Messenger desktop app
SwiftUI Reddit client
Use any mail/calendar client with an Exchange server
dejalu
Customer service platform
Filesharing using Direct Connect and ADC protocols
Unofficial ProtonMail Desktop App
Mastodon web client
Unofficial native application for Fastmail
Run Genesys Cloud as a stand-alone program, keeping it separate from web browser
google-chat
Email client
Desktop application for Instagram DMs
Low-latency rehearsing, jamming and performing
Team communication and collaboration software
Online conferencing software
Desktop client for Misskey
IRC Client
Social network built on the peer-to-peer SSB protocol
Unix terminal client for Mattermost
Discord rich presence client for Jellyfin and Emby
Native desktop app for Messenger (formerly Facebook Messenger)
Facebook's Messenger Native