The Dragon: Shadow Moon up until Moonrise Part 4. After his death, he's replaced by Wolzard.
Expy: Both Rage Rider and Suave Rider draw influences from Momotaros and Urataros respectively. Suave Rider even lampshades this when he sees just how low Urataros sunk in the Imagin Anime.
G-Rated Drug: The Energy Memory. Now, while all the Gaia Memories are G Rated Drugs in their original show, The Energy Memory takes this straighter than even how Kamen Rider Fourze portrays the G-Rated Drugs, as it makes EZ downright high while giving him an energy boost after using it in his review Godzilla vs. Megalon.
It does not help that Smoke on the Water is playing in the background when he does so.
It starts to get treated more of a drug than a simple Transformation Trinket now, complete with addiction, Rage Rider calling him out for using the drugs, and EZ quitting it cold turkey.
Heroic Sacrifice: Rage Rider heals up EZ Rider right before being killed by Shadow Moon.
Shout-Out: In Moonrise Part 3, Hidari Shotaro (as portrayed by EZ) comes and gives him both the Skull Memory and Skull Magnum the exact same way his mentor gave him the Lost Driver in Double's Movie. Lampshaded by EZ.
The scene in Moonrise Part 4 where EZ gains the power to transform into Black RX is similar to Kaizoku Sentai Gokaiger's "unlocking the greater power" moment.
In that same video, The Big Bad kills The Dragon due to him failing one too many times then hires a new one, who remarks that Shadow Moon was a fool and that he will do better. This is reminiscent of the first season of Sailor Moon, where Jedite falls (in the exact same way) and Queen Beryl hires Nephrite to succeed where Jedite failed.
Something Only They Would Say: Inverted. Rage could tell that EZ is not himself because he called the Dekaranger ending his favorite song, when he previously stated he hated it.
The Stinger: In Moonrise Part 4, Mr. Chairman hires a new solider after Shadow Moon failed him for the last time, and it's Wolzard.
Stock Footage: EZ uses footage from Kamen Rider Black for most of Shadow Moon's moments. Lampshaded during Moonrise Part 4 when EZ mentioned that he uses Stock Footage and Shadow Moon turns around, asking him "...What Stock Footage?"