This fictional newspaper from the Central City Citizen has been part of the series since the pilot, but Season 3 provides critical "on-paper" developments:
: Many new copies included a paper slip with a Digital HD UltraViolet code , though many of these have since expired. The Flash Season 3 Complete Pack
: Standard DVD and Blu-ray packs typically include a printed insert or booklet that lists all 23 episodes and descriptions, such as "Flashpoint" and "Finish Line". This fictional newspaper from the Central City Citizen
: The paper serves as a constant reminder of Barry's eventual disappearance during a "Crisis". : Often lists the Gold-colored Steelbook for approximately
: Often lists the Gold-colored Steelbook for approximately $65.00. Amazon : Carries the standard Blu-ray and DVD versions.
The "interesting paper" you are referring to is likely the with the headline "Flash Missing, Vanishes in Crisis" . While this paper appears in several seasons, it is a central plot device in The Flash: The Complete Third Season because Barry travels to the year 2024 to investigate the identity of Savitar and witnesses future events tied to this specific document. The 2024 Newspaper
If you are looking for physical paper collectibles included in the box sets: