This is based on opinion. Please don't list it on a work's trope example list.
Tear Jerker / Choujin Sentai Jetman
The three rangers from the reverse dimension are all killed by Radiguet, the last one gets a emotional death scene before dying from his wounds.
The whole fate of G2 is a massive Tear Jerker: Rejected by Tranza for being inadequate, (although being a robot he could have been easily perfected), he was given to the Mooks to be effectively tortured. That he made childlike screams didn't make it better. After he succeeds in fleeing, the wounded G2 is helped by Gray only to be rejected again. He tries to help Maria and Gray only to die alone and unmourned. The Jetmen don't even know of his existence. It is impossible to not feel depressed after watching that.
The deaths of Rie, and later, Gai.
Gai's death has additional layer of Fridge Tear Jerker. While Gokaiger does reveal the Jetmen and Aya eventually did find out about his death, as shown with his grave, the fact that we still didn't see what happened when they did has to make one wonder, especially the implication that a happy day such as Ryu and Kaori's wedding quickly became a sad day.
Episode 21. If the way that Ako's relation with Pooh-Tan is shown, there is the way the Teddy Bear turned Jigenju is treated by society and his death. To add even more, there's a HUGE Take That in the episode's ending. One has to wonder how many are annoyed with the ending...