Twitter may soon launch Twitter Blue, a premium tier service that comes with features like delaying tweets, changing threads to more readable formats, and changing color themes. However, there has yet to be an official announcement. Further, many of these features are available through free web services or third-party apps.
https://www.notebookcheck.net/Twitter-may-soon-offer-premium-Twitter-Blue-service-for-US-3-per-month.541459.0.html