I've been making a modern Slack terminal client (https://github.com/gammons/slk) and it's been a joy to use daily. There are a few things that IMO have unlocked a fantastic TUI experience:

- TUI libraries like Lipgloss and Bubbletea really allow users to build a rich experience nowadays. Really anything from https://charm.land is well-polished and a joy to use.

- Kitty image format works great and allows for Avatars, image previews, etc, which helps immensely make slk feel like a Slack client and not an IRC client.