Source: FANDOM Wikipedia

Kamen Rider Brain

In an April Fools' joke for 2017, the official Kamen Rider Drive Twitter announced a V-Cinema "Drive Saga: Kamen Rider Brain" which will be released in 2035, throwing back to Brain's line about being the next to become a Kamen Rider at the end of Kamen Rider Heart. The joke post was made to commemorate the closure of the account.

Two years later, however, it was confirmed that there will be 2-part web series on Toei Tokusatsu Fan Club.

Kamen Rider Amazons : The Last Judgement

As an April Fools' joke for 2018, the official site for the movie changed the official poster image to a joke image showing Amazon Alpha and Omega posing together in a flowery background, so as to show that the Amazonz were "living in peace". 

A joke trailer was also released featuring actors Masashi Taniguchi and Tom Fujita as their respective characters Jin Takayama and Haruka Mizusawa acting out of character. The end of the trailer also showed a brief scene where Rena Takeda, portraying Mizuki Mizusawa, is seen leaping happily together with Amazon Alpha and Omega.

Kamen Rider Genms: -The Presidents-

An April Fools' joke in 2018, the official Kamen Rider Ex-Aid Twitter announced a new season named "Kamen Rider Genms: -The Presidents-" ,which will be released and discontinued at the same time in 2020, featuring Masamune Dan, Kuroto Dan, Ren Amagasaki and Tsukuru Koboshi. The four presidents will rise to change the world and the shareholders. The title is an in-joke to Kamen Rider Amazons and series writter Yuya Takahashi also joked that he will write this.