Metalder's appearance is reminiscent of Kikaider in that the left half of him is red and the other blue. Kikaider's outer shell is half-blue and half-red because of his incomplete conscience circuit (if it was complete he would only be blue, as blue signifies "good" in the Japanese culture. while red represents "evil"). Metalder is different in that his left side is complete and his right one has exposed circuits.
Like Metalder, Kamen Rider Double's HeatTrigger Half Change is also reminiscent of Kikaider. However, while Kikaider's left side his red and his right side is blue, HeatTrigger's right side is red and his left side is blue like Kikaider 01.
Kill la Kill
In episode 18, Into The Night, the Life Fibers gain control of the students at the academy. Once under mind control their brains become visible, giving them a resemblance to Hakaider.
In episode 38 of the series, the team gets sent back in time to prevent Takeru from being erased. The younger Takeru is shown in a flashback wearing a homemade version of Jiro's costume and performing his transformation pose before jumping off a roof and hurting himself.