Mythology Gag / Kamen Rider Zi-O

• Many of the clocks and knick-knacks in Junichiro's shop are props that were used in previous seasons. Some were not the exact piece used, but are of the same model and appearance.
• Zi-O's name calls back to both the last 20th anniversary Rider (ZO) and the last time travel Rider (Den-O).
• An internal one, but Decade Armor resembles the design of the player created Ganbarider from the Ganbarizing arcade game. Decade's card gimmick was made as a tie in to Ganbarizing's predecessor, Ganbaride and so Decade Armor carries on the spirit of its namesake.
• Zi-O was born in 2000, the year Kamen Rider Kuuga premiered and started the franchise's Heisei era.
• The naming scheme for the Another Riders is the same as that of Another Agito. The Another Rider for Agito turns out to be a particularly twisted mythology gag - while certain humans could potentially evolve into Agito, Another Agito only existed because the real form of Agito was taken by Shoichi Tsugami and his sister before that. In Zi-O, humans are forcefully evolved into Another Agitoes whether they want to or not.
• During Woz's opening and ending narration (from Episode 2 onwards), Cronus's clock can be seen behind him.
• Two relating to Ōma Zi-O:
  • His "Rider/ライダー" visor is vaguely shaped like a bird similar to Shocker's symbol.
  • Him being an evil version of Sougo who becomes a Demon King in a Bad Future makes him similar with Future!Kotaro Minami in the manga adaptation of Kamen Rider BLACK.
• The horns on Another Fourze's head bring to mind Kamen Rider Specter. In fact, in Kamen Rider Ghost: Legendary! Riders' Souls!, Specter uses the power of Fourze Damashii to destroy a resurrected Sagittarius Nova.
• Another OOO is transformed from King Kuroto Dan. The first and original OOO was a King in a distant country in European region.
• Another OOO has several to Kousei Kougami from the original OOO series.
  • When he first obtained his powers, he called it "Magnificent^note Subarashii", Kougami's Catchphrase to describe the birth of a new development.
  • His megacorporation Dan Foundation is one to Kougami's Kougami Foundation.
• In a Freeze-Frame Bonus, Dr. Maki's doll can be seen in the background of a few of Dan's scenes during the OOO arc.
• Another Zi-O's helmet design actually takes considerable inspiration from Kamen Riders 1, 2 and the Shocker Riders, with a pair of red bug eyes behind the visor, a jagged mouthpiece, and the metal piece in the middle of his head.
• Instead of red bug eyes which main Riders and their Another Riders had, Another Blade has a pair of human-like eyes. Possibly a reference to Tachibana's final fight with Giraffa Undead wherein his Rider helmet's eye cracked and partially exposed his face, alongside a blood leak. In addition, Another Blade's facial design also resembles Hajime's infamous "I will kill you!" expression from the home series.
• Another Hibiki's name being labelled vertically references how the original series' logo was also vertically oriented with the words read from top to bottom.
• Another Kabuto's belt buckle is a yellow larva with red markings curled into a ball, which evokes the design of Kamen Rider Stronger's Electrer belt; Kabuto was specifically designed to be an homage to Stronger.
• Another Drive's head evokes Super Deadheat Drive from the movie Surprise Future by having a half-and-half design, but it is taken a step further by her human-like left eye, which references the specific scene where Dark Drive beats Shinnosuke so badly that the left side of the Drive helmet breaks and exposes his face underneath it. This is foreshadowing, considering that Dark Drive was the Paradox Roidmude.
• The bars on Another Decade's horns and head resemble a twisted version of Decade’s emblem, with his head in the middle and six bars on each side of the head.
  • The overall design of Another Decade recalls Decade's Crossover with Samurai Sentai Shinkenger, where an Ayakashi managed to steal Kaito's Diendriver and transform into a distorted, monstrous version of Kamen Rider Diend.
• The three Riders in the Over Quartzer movie are homages to Heisei-but-not-Heisei Riders — that is, series that aired in Japan's Heisei era, but aren't counted in the franchise's Heisei group. One is based on Black RX; the second is a shared reference to Shin, ZO, and J; and the third homages Amazons. The movie also features cameos from a variety of other works outside the main series, including Kamen Rider Zangetsu Gaim Gaiden, Kamen Rider Brain, Kamen Sentai Gorider, Kamen Rider G, the manga version of Kuuga, and even an unofficial parody Kamen Norider!
• Sougo's former classmate Owada is effectively a gender-flipped Nico Saiba.
• Kamen Rider Tsukuyomi's design and henshin pose is one to Miho Kirishima/Kamen Rider Femme's. Her crescent moon-shaped visor is also reminiscent of Zangetsu's.