Digimon character Justimon is a pair of bug-eyes away from looking like an official Rider: he has the outfit, the poses, the kick as a signature move, and even a red scarf. However, Stingmon, being an actual insect, has a bug-eyed body and especially head that makes him extremely Rider-esque. Sadly, that's the extent of the homage, if indeed homage is intended.
Shin-chan has a character called "Action Kamen" (called "Action Bastard" in the dub) who is basically a Kamen Rider clone. Humorously enough, it comes full circle with Shin-chan having crossovers with both Den-O and Fourze.
Detective Conan has Kamen Yaiba/Masked Yaiba, which is the favorite show of the Detective Boys.
The Great Saiyaman from Dragon Ball Z downright parodies Kamen Riders (and toku heroes in general) yet still manages to be awesome.
Two of the Lucky Star live-action EDs involve Minoru Shiraishi playing with a Den-O belt ("Shi-kaaaaaaideeeeerr!!") and mimicking Rider-1's transformation pose on a hillock (the sped-up Motteke! Serafuku).
Don't forget about Konata's father (playing with static electricity). "STUROOONGAAAAA!!!"
Asura's Wrath: Along with wearing a mask (though not beetle like), Yasha uses the mother of all Rider Kicks to deflect a giant Death Star-like laser cannon forming from the Karma Fortress's head (which is bigger than the moon!)
Eureka Seven Volume 1: The New Wave, the video game of the franchise, has a move called Rider Kick, usable by the protagonist and the last melee move you can learn in the game.
In King of Fighters, one of Leona's supers makes her impale her opponent on her claws, everyone freezes as sparks fly out of the enemy, and then Leona pulls out her claws and poses while the opponent blows up, all done in a fashion that suspiciously resembles Kamen Rider Black RX's finishing attack (although RX does it with a sword instead of claws). Also notable is that her jumping CD attack is identical to the iconic Rider Kick, right down to the inexplicably glowing foot.