W 48. I've seen it a few times in the thread, but still. how they're standing there talking and Shotaro's reluctant to undo the transformation from Extreme, knowing that he'd be there by himself. What got me was how Philip was mostly calm through the whole thing until right at the end. I'll admit, I shed some tears on that episode, and the part that got me was right at the end of the episode when Shotaro found Philip's book and he made his promise to keep fighting as Kamen Rider.
Blade 49: Kenzaki sacrificing his humanity to bring the Battle Royale to a standstill by turning himself into an Undead. Even though Blade wasn't one of my favorites, that episode with Kenzaki turning into an Undead and Hajime seeing him only for him disappear again. One of the better finales that I've seen.
Kabuto 46: Tsurugi's death at Tendou's hands. Misaki screaming at Tendou to stop before he killed Tsurugi made a big impact on that episode, and Tsurugi's backstory as well, how the Tsurugi personality took over the Scorpio Worm's personality gave me shivers. Tsurugi was one of my favorite Kabuto characters, and the end of that episode where he died in Jiya's arms was definitely one of the sadder moments in Kabuto to me.
Den-O: Episode 28 when everyone but Momotaros turned back into sand. Ryoutaro kneeling beside the pile of sand and finding the phone and the look on his face. Zeronos watching his memories of Airi rusting up and fading to power up his Zero Form. Seig asking Ryoutaro for help when he was starting to disappear, and the despiration in his voice at the same time. Kintaros' sacrifice at the end of 47, taking the Belt from Ryoutaro and giving him a chance to get out of the way so that he could fight, fulfilling his wish. Ryoutaro and Yuuto's reactions about losing the Imagin was one of the stronger scenes in the show for me.
I'm pretty sure that there's a lot more but I can't remember all of them right now.