Feature Promotion Card / Announcement
Linear has a reusable channel in the bottom left of their UI to launch promotions. The channel houses floating cards and generally advertises new features, product launches, marketing efforts, etc.
The card is well designed and interactive with the cursor, and it can be dismissed for users who are not interested, too. Once clicked, it opens up to a modal with more information for the user, after which the card does not show again.
