The transformation and fight scenes after they unlock a team's power are a blast of nostalgia for fans of the past sentai.
The puppies in #9.
In #12 when Joe realizes that even though the Cid he knew is gone he still has friends and the flashbacks to how the crew met for the first time (complete with Luka punching Don in the gut).
Marvelous' complete trust in Joe that he will be back no matter what. Also, Marvelous and Joe's first meeting, showing Marvelous' softer side.
Specifically, Joe was being hunted down by a Zangyack execution squad after he had defected from them, refusing to kill a group of children. Marvelous was lamenting another devastated planet only to see Joe about to be killed and intervenes. The two kick major ass together. Joe warns Marvelous that he may not want him on the crew due to the electric collar around his neck that will electrocute him should he try to take it off, and potentially kill him. Marvelous' response is to rip it off anyway and take part of the electricity into his own body!
#15 puts the flashback from episode 2 in deeper context. Instead of Marvelous being saved by a heroic stranger he was saved by his captain and friend Aka Red who may have died to save him.
#16 shows us how much Marv cares for his crew. Particularly heartwarming is his semi-mute, but very endearing "Thanks, guys" in the end of the episode.
And in #22 he finally gets to change into Kiba Ranger, and again in #33 accompanied by the rest of his teammates as the core Dairangers.
In #18 even after he's hit by a truck Gai still manages to give a little girl a flower.
The premise of #19. More so the revelation that Navi gave to Don, that Gai thought he's cool, where Don up until this time had felt like he was in the way when around Gai.
#20 shows that although Ginga Red still doesn't trust the Gokaiger, he believes in them. The reason? Their bonds of friendship.
Wasn't that Black Knight Hyuuga? Ginga Red appeared too but was more friendly, and only directly interacted with the Gokaigers when saving them from their fall.
No, but Ryoma said that at the end of the episode while the Gokai Galleon was departing the Ginga Forest.
#21 shows some of the early days of the Red Pirates, and an adventure between Marvelous and Aka Red. Seeing Marvelous's eyes shining when looking at his captain will make even the coldest among you crack a smile.
#22 gives us a boy that made a promise to his friend that they would meet at the top of a mountain to watch a meteor shower. He went so far as to ride on his bike from Tokyo, a feat Gai exclaims had to have taken at least half a day. Seeing him throughout the episode as he tries to, and ultimately keeps his promise makes the entire team smile.
In #23, Ahim telling Luka that she's not Luka's dead little sister, Fia, and doesn't need to be protected. By the end of the episode, the 'big sister/little sister' roles has switched from Luka to Ahim, to Ahim to Luka.
The end of #24, where Jealoushitto found love (with a human!) and happiness.
While it is pretty heartwarming for Jealoushitto, it could be a Tear Jerker for the takoyaki store owner, as that human who fell in love with Jealoushitto was his mom. And both of them went away from him. There's a reason why sad music is playing instead of a happy one.
Then here's a replacement moment then, the episode's overall message of "No matter how different we may look, we're all the same when you think about it." counts.
The ending of #26, with some good fun had between the Gokaigers and the Hurricangers. Also, the fact that the team took punishment to save the people turned into nuts, which is also quite awesome.
And just before the Gokaigers and Hurricanegers start their team up fight, a single line (rather, a single word) from Joe: "I'll be counting on you, Senpai." Which doesn't seem like much, until you realize that Joe never refers to the previous Sentai warriors by that honorific, and otherwise uses it only for Cid, his late best friend and mentor. Really says something about how the Hurricanegers impressed him.
Gai Yuki's grave in #28, complete with presents from the other Jetmen and the inscription "Black Wing sleeping here forever"
Also the part where the Gokaiger Gai states that Jetman Gai seems to have returned to make sure his old teammates wouldn't get caught up in the Gokaiger's fight with Kiaido.
In #30 When Joe learns that Barizorg cannot be reverted back to his old friend Cid he breaks into tears and calls himself a fool for thinking he save his friend when and Liveman's Joh tells him it's natural to feel that way. He then follows by talking about how his friends turned evil and that he couldn't save them, and that he became a teacher at their old school so that future students wouldn't make same mistakes and believe he at least saved Tsukigata and Senda's souls.
#32 is one long moment of heartwarming centered around Don. It's all about his bond with the rest of the team giving him the determination to keep at his task of creating a new weapon, resulting in the pretty kickass Gokai Galleon Buster!
Don teaching the kid the value of teamwork and encouraging him to keep at his dream of playing soccer.
The entire team, starting with Marvelous, giving Don their weapons, knowing it would leave them unarmed in the case of an attack in order to help him with his project. Then they fight the monster of the episode unarmed to buy Don the time needed to finish the weapon!
#34 brings us Luka's old friend Cain, and reveals why Luka is so greedy to begin with: she wants to buy an entire planet to give a home to all the children orphaned by the Zangyack. Plus there's the rest of the team immediately catching on that the fake Luka is an impostor, showing how well the team knows each other, along with a flashback to how Marvelous and Joe recruited Luka to the crew.
in #37, I think the small chat Walz Gils has with Barizorg was pretty heartwarming. When he admits that he knows that most people find him incompetent and admits that he'd be alone if it were not for Barizorg got to me. Brainwashed or not, Barizorg shows his dedication like a true soldier to his leader.
After Barizorg is finally defeated in #38, Joe and Cid have a conversation in which Cid is proud that Joe has gotten stronger thanks to his companions and that Joe has saved his soul. Cid then tells Joe to move on to be with his friends, Joe thanking Cid as he leaves.
Aka Red and Marvelous' conversation. While Marvelous has tried to be like Aka Red, the latter dismisses that mindset and says that Marvelous should be more like himself and protect the bonds that he and the rest of the Gokaigers have shared and chase their dreams together.
In #40, the Timeranger tribute episode, ends with Gai sending Domon (Time Yellow) a photo the Gokaiger took with a young boy they saved as well as his mother. Domon initially grouses about the Gokaiger not focusing on the task at hand, but trails off when he realizes that the mother is Honami, the woman he loved and had to leave behind, and that the boy is the son he never knew. Cue the waterworks, both from Domon and the audience.
A meta example from the Gokaiger/Goseiger movie: the inclusion of Ooiwa's "Dosukoi!", when pretty much everyone else gets The Other Darrin treatment.
To clarify, Ooiwa's actor Baku Hatakeyama unfortunately committed suicide, making him a perfect example of Author Existence Failure. Although there are reports that Tomokazu Seki actually played Ooiwa, the fact he was one of the few Warriors in 199 Heroes to have a significant line without appearing out of suit either pointed to "Dosukoi!" being a popular line or an affinity for the character. Either way, it was a nice tribute to both Ooiwa and Baku Hatakeyama.
Most of #41 is this, where all of the Gokaigers back up Ahim and help her to settle her score with the monster who was responsible for the destruction of her planet.
Not to mention learning the reason why Ahim wanted to join the Gokaigers in the first place, to become a symbol of opposition to the Zangyack empire for her scattered people across the universe.
Episode 43 has one near the end. After Don admits to the rest of the team that he made up the story in the paper as a joke, and isn't a hero, the rest of the team tells him that he is a hero, because he saved Marvelous.
Episode 44 has more than a few. The episode ends with Luka turning into Magi Mother and making it snow for the children so everyone has a white Christmas. Then the Gokaigers return to their ship and find a gift from "Santa Claus" Battle Kenya in disguise: the Battle Fever ultimate power.
In episode 45, the Gokaigers meet Ninjaman, who's down in the dumps about how his temper got him sealed in a jar for ten years, so he missed out on the Legendary Battle when he felt he should have been helping his friends. After they cheer him up and get him up to speed, Ninjaman returns the favor in the next episode when he saves the crew from the Mo TW's evil power.
Episode 46 has Ahim delivering the aesop of the tribute episode... while having Gai and Don both on her lap. It's a very adorable Ship Tease.
Episode 47 has a Gokaiger wanting to bring Sally, recently shot by Basco in an act of betrayal on board the ship to take care of him. If your guess is either Ahim, Don, or Gai, very good guess, but nope. It was Marvelous himself. He even knew it was probably a trap, but he did it because even if it was, Basco was just going to betray Sally like Basco betrayed him and Aka Red. He was trying to protect Sally from suffering like he did. Marvelous being the merciful one shows a sweeter side he usually saves for his friends makes this truly heartwarming.
While Marvelous is brooding on the mast, Joe comes up and asks what Marvelous is thinking. After some thought, Marvelous realizes that, even though they've probably entered a trap, he can't just abandon their guest having endured a similar betrayal himself. Then he promises that they're not taking Sally onboard, and that once said guest's wounds have healed they'll drop them off. Joe's reply is that, after what he went through, managing to pull together such a ragtag crew is pretty impressive, and basically says he'll trust Marvelous if he wants to add their passenger to the crew. Sadly it doesn't happen, but the kindness everyone shows results in Sally sacrificing herself to save Marvelous.
#50: Also a Moment Of Awesome. The Gokaiger are already aware of what will happen if they use the Greatest Treasure to rid the world of the Zangyack and restore their home planets note The Greater Powers of the past 34 Super Sentai, and the warriors themselves, will be lost forever. But even if they used the Treasure, they would not be the people they are now. Instead, they allow Gai to decide what should be done because he has an opportunity to save his home planet; an opportunity they never had. But Gai, shedding Manly Tears, chooses to destroy the Treasure and fight for his home as the Sixth Ranger!
All the team runs into people who show them just how important the Super Sentai are to the people of Earth, and bolster their courage. Marvelous encounters the kid who stole his Mobirates and the Shinken Red key way back in #2, and tells him that he's found things of value everywhere on the planet.
The finale's closing moments. The Gokaigers scatter the Ranger Keys to the wind, and we see them being returned to their original owners, ending with Aka Ranger telling them they did a good job. The series comes full circle.
Gokaiger vs. Gavan: Marvelous not hesitating to go into Makuu Space to rescue Gavan, all so he could repay Gavan for saving his life in the past.
Gavan still remembers their single meeting all these years later, and tells Marvelous that he's proud of how he grew up. Marvelous questions if that includes him being a pirate, and Gavan tells him that's irrelevant, because Marvelous is a good man and that's what matters.
In Gokaiger Goseiger Super Sentai 199 Hero Great Battle, there's several of these moments:
As they manage to deal enough damage to the Black Cross King to stagger him, Marvelous notices one of the sentai figurines glowing, and picks it up. It takes the form of Aka Ranger, the very first red ranger...which then gives Marvelous a small nod. That kind of approval and trust, coming from the first in a long line of distinguished heroes, is bound to give one's heartstrings a tug.
After the combined forces of past Sentai mecha defeat Black Cross King, crowds of civilians are cheering the Goseigers and the Gokaigers. The Goseigers take pretty much in stride, but the Gokaigers, based on their body language, clearly aren't as used togetting this kind of praise.