Analytics has a Channels tab: every channel you can see, quiet ones included, with its members, messages, people posting, reactions, when it was made and when it was last used. Every column sorts, you can filter by name or show only channels with no messages in the period, and Download CSV gives you the lot.
/me, /shrug, /tableflip and /unflip now work in a direct message or shared channel kept in another organization. Search has an Exclude automations switch, off until you turn it on. A Link’s message and your sidebar show who is in the call as soon as someone joins or leaves, even when you are not in it yourself.
Deleting a channel tells the people whose scheduled messages went with it. On a phone, Manage conversations, Todos, Preferences and channel details keep their words whole at the largest text sizes, and Jump to latest never covers the control you are on.