Kamen Rider OOO (2010)

Both shows share a dual of protagonists (Shotaro and Philip/Eiji and Ankh) who work together to fight the monsters of their respective series (Gopants/Greeeds). The transformation gimmick of both main Riders uses different kinds of combinations which allow them to activate various forms.

Fourze is the series following OOO so if you want to watch the Kamen Rider seasons in order then watch Fourze after OOO.

Both of these dramas get Anniversary before Fourze and Revice. The content of the story is also the same, but has the theme of Wild animals, God Beasts in one device with the title Story book in the same. also met his ancestors (Kamen Rider #1) for the first time in the history of the Kamen Rider franchise.