[Sunred]

I recently checked the live action Oshi No Ko casting and was surprised to see a few alumnis in it.

Haru Iwakawa as young Aqua (Jun Hiruma in Ultraman Blazar)
Nanoka Hara as Kana Arima (Child in episode 34 of Shinkenger)
Kazuto Mokudai as Ryosuke (Michinaga Azuma/Kamen Rider Buffa in Kamen Rider Geats)
Totaro as Nobuyuki Kumano (Tsubasa Inuzuka/Inu Brother in Donbrothers)
Jun Kaname as Masaya Kaburagi (Makoto Hikawa/Kamen Rider G3 in Kamen Rider Agito)
Hideyoshi Kan as Melt Narushima (Ace Ukiyoe/Kamen Rider Geats in Kamen Rider Geats)
Terunosuke Takezai as Himura (Kotaro Shirai in Kamen Rider Blade)
Mirai Shida as Abiko Samejima (The Girl in episode 49 of Kamen Rider Ryuki)
Aoi Nakamura as Sumiaki Raida (1970's Kotaro Minami in Kamen Rider Black Sun)
Junki Tozuka as GOA (Shunpei Nara in Kamen Rider Wizard)