- The theme song; then again, an awesome theme song seems to be mandatory for a Kamen Rider series.
- The various theme songs of OOO's forms, whose titles are a play on the combo's name, are all strong contenders. Each one, being sung mostly by Eiji's out-of-suit actor Shu Watanabe, has a specific relevance to his character.
- #5: "Regret nothing ~Tighten Up~", the theme song of TaToBa Combo. The song is also the default used for the Random Combos that don't have a theme; the TaToBa beats are removed in these cases, of course. As it's made for OOO's basic form, the song is primarily about the promise Eiji made to always help someone in trouble, and that he has, well, no regrets over how hard he's had to fight to make sure peace is restored. The song sets the mood for the others; upbeat, a bit wistful, but ultimately hopeful.
- #6: "Got to keep it real", the theme song of GataKiriBa Combo. Using a combination of electric guitar and what sounds like a guiro, it has a fittingly jumpy beat for a bug-themed power set. The lyrics speak primarily to the motto of Be Yourself; You can't always hold out for a miracle. Just do what comes natural and you'll never go wrong.
- #9: "Ride on Right time", the theme song of LaToraTah Combo. This one takes more of a rap-styled edge, with a fast-paced aggressive mood to match the predators the combo is named for, and is about staying focused and keeping your head clear.
- #12: "Sun goes up", the theme song of SaGoZo Combo. A far more plodding, deliberate rhythm underscores this song to go with the theme of beasts of burden. The lyrics encourage you to look on the brighter side if things are looking dark, and if that bright side is threatened, to crush the darkness underfoot.
- #20: "Time judged all", the theme song of TaJaDor Combo, a duet by Eiji and Ankh, and also happens to be their Image Song. The song opens with an ominous German choir meant to evoke a sort of majestic feel. The lyrics are about Eiji and Ankh's personal relationship, and how despite butting heads, the two ultimately learn valuable things from one another, and unite to burn away the evils that threaten the world.
- #36: "POWER to TEARER", the theme song of PuToTyra Combo, a duet by Eiji and Akira Kushida, the voice of the OOO Driver itself. Going full metal, the song is about Eiji confronting the destructive power of the purple medals, learning the true nature of his own desires, and learning to control that power to become the savior he longed to be.
- Movie War Megamax: "Shout Out", the theme song of ShaUTa Combo. With a bright, happy melody underscoring its lyrics, the message is to go with the flow and listen to your gut instinct.
- #38: "Reverse/Re:birth", the theme song of Kamen Rider Birth. The song is unique in that it's covered by the actors for Gotou and Date separately, and also has a duet variant to signify the passing of the torch from Date to Gotou, as well as their ability to work as comrades.
- The "Combo Change Medley." If the Combo songs were awesome alone, listen to all of them together in one package.
- The movie theme song, Te wo Tsunagou, also counts as a Heartwarming Moment. Doubly so for the full orchestra version.
- The OST has a handful of powerful tracks to offer too.
- T#17: "The Transforming RideVendor". Fast, guitar-based RideVendor action theme.
- T#44: "Resolve". An audio representation of the "Determinator" trope.
- T#50: "Big Brother and Little Sister". As you can guess from the title, it's generally used in scenes involving Ankh/Shingo and Hina. But unlike the other upbeat songs listed here, this one is rather sad and melancholic, and in a handful of instances where it's used in the series, it certainly delivers the emotional weight of the scenes.
Awesome Music / Kamen Rider OOO