Campbell-edited future historians. On the other hand, five particular future histories (maybe) form a literary sequence:
Heinlein, the Future History;
Anderson, the Psychotechnic History;
Anderson, the Technic History;
Larry Niven, the Known Space History;
Jerry Pournelle, the CoDominium History.
modeled the Pschotechnic History on the Future History;
made Rhysling from the Future History a guest in the Old Phoenix;
wrote one story set in the US Robots period of Asimov's future history;
wrote three stories set in the Man-Kzin Wars period of the Known Space History;
wrote one story set in the War World period of the CoDominium History.
Heinlein advised Niven and Pournelle on the first of their joint novels set in the CoDominium History. Niven and SM Stirling contributed separately to War World whereas Pournelle and Stirling contributed jointly to the Man-Kzin Wars. And I may have missed some details here.
Addendum: I did:
Pournelle and Stirling contributed jointly to the Falkenberg period of the CoDominium History;
Niven adapted a Known Space story as a Star Trek animated episode and Alan Dean Foster adapted the episode as a prose story.