Taka Medal: Dropped by Eiji which fortunately Shotaro throw it back to him in Kamen Rider W movie, used by Eiji to access Tatoba Combo to fight Luna Dopant. And later in the series finale it would broken into two pieces and serves as memento of Ankh which Eiji always carry it during his journey.

Newton Eyecon: Appeared in Episode 48 of Kamen Rider Drive, this Eyecon are a vital item in order to save Kiriko who's held hostage by Keisuke Okamura the leader of Neo-Shade. Later in the series of Ghost, Takeru would use it to access Newton Damashii.

Shakariki Sports Gashat: In Kuroto's possession he test the Gashat only to be stolen by Ayumu who claim that this Gashat can "change the world". Later it would be taken back by Kuroto and use it in the series.

Ex-Aid Fullbottle (LV1 version): Extracted from Emu by Takumi Katsuragi (later Sento Kiryu). Later this Fullbottle would be purified by Misora, turning it into Doctor and Game Fullbottles allowing Sento to access Ex-Aid Form and this would help Emu regain his power.

Cross-Z Ridewatch: Already in the hands of the genius scientist Sento Kiryu after the merge of two earths to defeat Evolto and save the world. Later in Zi-O, it would be given to Sougo Tokiwa by Ryuga Banjou for his journey to become the demon king.

These are all the items that plays important roles be it pre-series and in the series.