Ur: "With my two bright pupils growing day by day... Every day an adventure... That's all the happiness I need."
Episode 20 easily qualifies. We see a little more than in the manga the relationship that Natsu and Lisanna had when they were younger. It's also a little painful to watch when you know what finally happened to Lisanna.
The friendship of Natsu and Happy brings on the Heartwarming here too. Happy's origin story establishes that he made everyone in the guild happy (where he got his name), after the tension built between the guild members. After he and Natsu get into a falling-out, Natsu remembers that they're like family... and reconciles with Happy by bringing him a whole bunch of giant fish! Awwwwww.
Lucy, kidnapped by the Phantom Lord guild, takes the standard trust exercise to its extreme by THROWING HERSELF OUT A TOWER WINDOW. Why? She heard Natsu in the distance and had complete faith that he'd catch her...and he does.
Lucy: "I won't stop til the gate's open! I won't let you die! What's the point of having magic power... if you can't use it to save the people you care about?"
The grand finale for the Tower of Heaven arc has Natsu carrying Erza on his arms after she thought about sacrificing herself to suppress the Etherion power from going loose; doubles as a Ship Tease with Erza crying in his arms.
Erza: "You don't die for your friends... you live for them."
The end of Chapter 100 in the Fairy Tail manga where Erza is revealed to be alive, and for the first time sheds tears of joy.
Arguably, Chapter 105, when Gajeel, after being allowed to join Fairy Tail (invited by Juvia and Makarov), is confronted by Jet and Droy of Shadow Gear, the team he attacked and practically crucified to a tree when he was with the rival guild Phantom Lord. He acts arrogant, but takes all their hits while Levy (the one most affected by the attack) watches. Laxus, one of the S-Class mages from Fairy Tail, arrives, and attacks Gajeel in a rage about how people believe Fairy Tail to be weak. Still, Gajeel takes the attacks, making Shadow Gear realize that he wasn't fighting back because he wanted to be recognized as True Companions by them and everyone else. As Laxus continues to beat on Gajeel, the team tells him to stop, but he answers by attacking them with magic. The attack heads for Levy, only for Gajeel to jump in front of it just in time. For someone who didn't seem to particularly care about anyone previously, this is quite the heartwarming moment.
This troper considers the entirety of Chapter 127, but especially the interaction between Natsu and Laxus, and Makarov's talk with Laxus, ending with Laxus's excommunication from Fairy Tail to be both this and a Tear Jerker. Especially the last two pages.
Laxus invokes Fairy Law on Magnolia, but no one dies because regardless of all his tough talk, inside his heart he doesn't consider anyone of Fairy Tail or Magnolia as his enemy.
All of Fairy Tail's members doing Laxus's sign at the same time upon his departure is also smile-worthy.
Chapter 144, when Angel of the Oración Seis commands Gemini to kill Lucy.
Gemini: "Lucy loves us from the bottom of her heart... Us Celestial Spirits..."
The Reveal at the end of the Oracion Seis story arc is a Tear Jerkerand Heartwarming: We find out Wendy's Guild Cait Shelter isn't a real guild: all their member, minus Wendy and Carla, were illusions created by Robaul so Wendy would have friends and a guild to live with. Think about it: Robaul created an entire Guild out of illusions, and maintained it for years, just to make a little girl happy.
Episode 76 is part tear jerker, part heartwarming.
Natsu:(lying in a river, staring up at the sky) "Are you doing okay, Igneel? ...Dad?"
Chapter 177: Happy and Carla are given refuge after they rebel by an old exiled couple outside the city. They tell them they were exiled because they opposed an operation 100 years ago when their eggs were taken from them for a "Dragon Extermination Project". Happy and Carla leave the house without being told this, but it's quite clear that they are Happy's parents. Cue tears.
The end of the Edolas arc, when Natsu acts as the Big Bad in order to unite Edolas under Mystogan. Then he gives the three rules for anyone leaving Fairy Tail to Mystogan, and all of Fairy Tail and the Exceed being sucked into the sky back home.
Natsu: "You must never consider your own life to be of little value and you must never-"
Mystogan: "Forget about your friends, who loved you..."
Basically, anytime somebody is given the farewell ceremony is this along with Tear Jerker.
Juvia and Lucy teaming up in the Tower of Heaven arc, and becoming friends.◊ Juvia even cries when Lucy accepts her as a friend, since nobody has ever treated her so kindly before.
There's also the speech she made to Lucy about loving Fairy Tail, even in the midst of being Brainwashed and Crazy.
Juvia: "Lucy-san...Juvia doesn't want to hurt her friends...Although it's a little presumptuous of me to call you that, after all you are my rival in love...Juvia has truly come to love Fairy Tail...it seems so friendly...so fun...so warm...as though even if it's raining outside in the guild the sun is always shining..."
Juvia intentionally sacrificing herself to get her and Cana out of Fried's enchantment, just to gain acceptance in the Fairy Tail guild. Cana tearfully insists that she was one of them all along. Doubles as Juvia's Crowning Moment of Awesome.
After Mirajane's Crowning Moment of AwesomeCurb-Stomp Battle against Freed, a memory of Lisanna keeps her from killing him, she reverts back to normal and reminds him of all the friends he has in Fairy Tail, holding his hand as he cries and admits to never wanting to be a part of the battle.
After Lisanna returns to Earthland, the first thing she does is hug Natsu and explain everything that happened, from being stuck in Edolas to her tearful farewell to the Edolas versions of Mirajane and Elfman, who knew all along that she wasn't their sister. She then goes to Caldia Cathedral, where she is reunited with her brother and sister as they are visiting her grave. Their faces of shock say it all, and the family is then brought together in a single hug.
Mirajane: "Welcome back."
The Fairy Tail members hold a rambunctious part after they return from Edolas, and the next morning, Lucy is the first to wake up... to see the Strauss sisters sleeping in a deep embrace. They're making up for all the time Lisanna was taken from them. Lucy smiles.
Wendy, Chapter 167, after being reunited with Mystogan. Her Cry Cute makes it even more heartwarming.
Wendy: "You're the one from seven years ago... Jellal, back then... I've wanted to... see you again for such a long time."
In Chapter 212, we find out that Makarov scouted Gajeel HIMSELF and we learn why he decided to let him join the guild. It's just the sort of thing you'd need to hear from a fatherly figure:
From the bonus chapter, when Lucy takes a look around Natsu and Happy's... house and sees his souvenir gallery from all the missions they've had together. Awwww.
A really nice one from the end of the Oración Seis arc: Hoteye's prayer was to meet his long lost brother again, who turns out to be Wally, Erza's childhood friend. When Erza tells Hoteye that is brother is doing well, Hoteye lets his tears out, and believes it is a miracle of the light side that he was able to find this out.
And later after the disappearance of Cait Shelter Erza comforts Wendy on her loss and invites her to Fairy Tail.
Erza: "Bury the pain of losing your loved ones... in the arms of your friends. Come with us, to Fairy Tail."
One of the omakes (animated as Episode 73) has Lucy out sick, causing her to miss the Magnolia Sakura Viewing. While in bed, she sees a beautiful multi-colored sakura tree, floating outside on the river. Turns out that Natsu and Happy did it to make Lucy feel better.
Also doubles as a Crowning Moment of Awesome since any girl would definitely fall head over heels for a guy who'd do something like that.
Episode 106: Mirajane shielding Lisanna from the time bomb she was trapped in and using her body to divert the explosion.
Mirajane:"I won't let you die again."
Chapter 224: Capricorn is revealed to actually be a benevolent spirit who was possessed by his master. After the battle, Loke asks if he'll lend her power. He replies no... as his power has always been hers in the first place.
Chapter 227: Lucy refuses to run out on Natsu when he's trapped under some boulders and she's clear out of magic.
Lucy: "I don't want... to run away by myself... Because no matter what... I'd rather be together with everyone."
Chapter 230: Juvia finally defeats Meredy. How'd she do that? Not by pure yandere-rage fueled ass-kicking, as it looked like would happen at first, but by overwhelming her with the The Power of Love.
"Even you smile! Even you have someone important to you, too!"
"I live for the ones that I love! You've got to, too!! If you have love in your life, then you must keep on living!!!"
Also counts as a meta example. According to his Twitter post, Hiro Mashima was still drawing out this battle when the March 11th Tsunami happened. He couldn't go with the original idea of Juvia winning using her powers because they all involved water, so he decided to go with the above scene to send a message to the victims of the tsunami.
Chapter 232: Cana realizing how mistaken she was on just focusing on the test. She's now rushing to save her True Companions with the power of Fairy Glitter imparted to her by the first master of Fairy Tail. A power right up there with Fairy Law.
Which she doesn't know how to use anyway. Bringing up another Moment of Heartwarming in the very next chapter, where she's saved by Gildarts, who was revealed to be her father a few chapters ago. It's unclear whether or not he knows this.
The end of the Fairy Hills omake and OVA. Lucy is made to look around the women's dorms by the elderly matron, Hilda, in a Stripperific Cat Girl costume. When she finally finds the treasure box, Erza tells her that Hilda has been dead for 6 years. When they open the box, it's full of jewels. Jewels that Hilda told Erza that she'd give to girl once she became an adult after seeing Erza pretend that she didn't need to accept one of the play jewels Hilda got for the children when she saw that there wasn't enough for all the girls. Lucy's monologue at the end clinches it.
Lucy: "People's feelings are connected. It transcends time, and it reaches your loved ones. I was able to feel that. And that's reward enough for me."
Chapter 241: As she fights with Gray, Ultear thinks about her past, about how Ur had abandoned her at a laboratory where she was subjected to numerous inhumane experiments, pushing her body and spirit to their utter limits. And when she finally escaped and made her way back to her mother, she saw that she had been replaced, which is what lead her to hate Ur as much as she does. This is why she joined with Hades, why she wants to create the Great World of Magic, and why she learned Arc of Time. With those two keys, Arc of Time, and the Great World of Magic, she could go back, back to when she and her mother lived in happiness. But when both she and Gray fall into the ocean, first a voice and then images begin to flow into her mind. Her mother, scared for her daughter's life due to excess magical power, begs the researchers to help her. Her mother, utterly broken when she's told her daughter is no longer living. It's that, and Gray telling her the one story Ur ever told her pupils about her daughter, that allows Ultear to realize just how mistaken she was about her mother, just how much Ur loved her.
Chapter 245 has this:
Laxus: "I'm no longer a member of Fairy Tail, but if something happened to the old man... I can still get angry about it, right?"
Natsu: "Of course you can!!!"
Chapter 250: Meredy forgiving Ultear and stopping her from killing herself.
Chapter 251: Cana revealing to Gildarts that she's his daughter and his reaction is this and Tear Jerker at the exact same time.
As is Laxus checking to see if Lisanna was real. And patting her on her head.
Wendy is intrigued by Laxus but a bit afraid of talking to him. Erza then assures her that Laxus is not really a bad guy, just one difficult to understand. Coming from Erza, and remembering the last time they where face to face they where brutally fighting each other, this says a lot.
It's also very heartwarming how Natsu tries to be there for Lucy and even drops his usual loud and brash attitude, shuts his mouth when she needs to think by herself (and makes Happy do the same) and in general shows a sense of situation that he doesn't generally have (except for when he ironically shouts loudly at some Valley Girls for not being able to read the air). When they get home, he even avoids participating in a fight, probably because he is busy feeling sorry for her.
Chapter 259: Gildarts reinstating Laxus back into Fairy Tail.
Chapter 262: Lucy's Celestial Spirits invited her and her friends to their realm to celebrate their homecoming.
Everything in this chapter, especially the song, is taken Up to Eleven in the anime.
Chapter 263: The mages of Fairy Tail meet up Jellal, Ultear, and Meredy. It's just one panel, but Juvia and Meredy reunite and aw... just awww.
Chapter 267: Porlyusica taking care of Wendy and Carla after being attacked by Raven Tail.
Mavis cheering on with the rest of Fairy Tail in the Grand Magic Games.
Both times Natsu stopped Gray from using Iced Shell. Particularly the second time, where Natsu stands in front of Gray as he's performing the spell, letting him know that if he wants to use that spell and kill himself, Natsu was going with him.
Gray: "Move, Natsu! Don't get in my way!"
Natsu: "I stopped you the first time because I didn't want you to die. Did you not get the message or something? If you wanna use that spell, go ahead."
Chapter 272: After Flare is declared the winner of the battle and Lucy is getting jeered on by the audience, Natsu helps a sobbing Lucy up and comforts her.
Natsu: "Don't cry, Lucy."
Lucy: "But...it's just so frustrating..."
Natsu: "Let's save the tears for when we win. You were amazing! Thanks to you, I realized that we could fight in this world. Zero points? That makes things interesting, right? We'll turn the tide now."
Lucy: "Yeah...I'm all fired up."
Heartwarming In Hindsight: This moment happened on Lucy's birthday, and Natsu eventually made good on his promise on the fourth day of the Grand Magic Games.
In Chapter 273, Jellal states that, even if it's only temporary, nothing could make him happier than to be able to fight under the Fairy Tail name.
Ren, in his usual Tsundere way, telling his fiancée Sherry how much he loves her.
Chapter 276: Natsu's answer to why Fairy Tail entered the Grand Magic Games. It moved most of the other guild members to tears and even made some spectators finally cheer for them.
This scene was even more heartwarming in the anime. It was voiced to perfection and captured every drop of emotion.
Several in Chapter 281. The first is Jellal being truly thankful that he and Erza can just speak normally to each other. A second is Erza and Millianna's reunion. The last one is Rogue comforting Frosch after the later started to doubt whether of not he could stay in the guild after Yukino was kicked out and Sting said she wasn't needed because she was weak.
Natsu gets one in Chapters 282-283 for storming into Sabertooth's grounds and challenging Jiemma to a fight after finding out what happened to Yukino.
Chapter 287: In addition to providing a kickass Curb-Stomp Battle, this chapter also shows off how much Laxus has changed since we first met him. If you were a member of Fairy Tail and were humiliated in a battle in front of the public, the old Laxus would just laugh or rage at you and/or the guild. The Laxus of now however, would be happy to pulverise the people responsible, just like the rest of the guild members.
Ivan: "Wait! I'm your father! We're Family! Are you going to hit your own father?!"
Chapter 289: After a heated battle that ends in a draw, Chelia offers to be friends with Wendy while healing her; the latter accepts her invitation and one of the judges even lampshades it by commenting on how heartwarming the friendship moment is.
Chapter 290: What was the first thing Elfman saw when waking up after his match? A sleeping Evergreen. She had been waiting the entire time for him to wake up. D'awww. What makes this a Crowning Moment of Heartwarming, and Ship Tease to boot, was that Evergreen had no real reason to be there. She was there because she wanted to be there.
Chapter 292: After the severe beating she got in the previous chapter, Lucy is resting in a hospital bed, and both Fairy Tail teams come to see her and make sure she's all right, even Gajeel and Laxus.
Chapter 299: A chapter without dialogue follows Gildarts in his travels as he saves a village. Later on, he's able to see what's going on with Fairy Tail in the Grand Magic Games through some sort of magic monitor in the saved village. Through it, he sees Cana's performance in the MPF. Being the proud papa that he is, he runs around telling all the villagers how great she is. You can just hear him say "That's my daughter!" as he runs around.
Chapter 300: After Jiemma lashes out at Lector, Rogue's immediate reaction is to wrap his arms protectively around Frosch and turn his back to Jiemma, who was attacking him just a moment ago, in order to ensure Frosch's safety.
Chapter 307: Natsu gets one, just for how adamant he was in taking part in rescuing Lucy from prison, that he gave up his spot in the Grand Magic Games to Juvia.
Natsu: "Making it... my enemy...? The question you should be asking yourself is... Are you really prepared to make Fairy Tail your enemy? If it's to protect our family, be it the Kingdom or the entire world... We would make anyone our enemy! That's what it means to be Fairy Tail!!"
Goes into Tearjerker territory when you realize that Erza essentially gave up her chance at freedom to protect Kagura. It was Kagura's crying that alerted the captors and then Erza gave up her hiding spot (which obviously worked). Still, Erza wasn't resentful. 'All she cared about was that Simon's sister was safe.'
Chapter 317: In the middle of his rematch with Gajeel, Rogue is beginning to fully understand how friendship works. Gajeel then clarifies he does have a friend in the form of Frosch. Her response?
Frosch: "Fro agrees!"
It gets even better when you remember this is Gajeel we're talking about here. One of the roughest members of the Guild both recognized friendship and reminded Rogue to cherish it. It just brings to mind how much Gajeel has truly changed.
Future!Lucy has doubts about whether everyone else will believe her story. Both Natsu and Present!Lucy assure her everything is going to be fine.
Natsu: "They would never doubt the words coming out of Lucy's mouth..."
Present!Lucy: "My future self shouldn't be filled with so much doubt. Have more faith in your Nakama..."
The amount of trust Natsu puts towards Future!Lucy after her revelation, as well as his putting his forehead against hers when she confesses that she didn't plan any strategy for the dragon attack.
Natsu: "Thank you. For the sake of everyone's future...I won't let it happen."
Chapter 322: Sting and Lector's reunion after Fairy Tail takes the victory, apparently thanks to Erza. This also doubles as a lovely Tear Jerker moment.
Chapter 324: Despite being placed in the middle of the Tear Jerker that is Future!Lucy's Heroic Sacrifice, Natsu's flashback of Lucy showing him her new guild mark from Chapter 2. It should be noted that while Natsu was shown seemingly uninterested in that chapter, the flashback revealed that he cared more than he let on about it.
And then there's the fact that he referred to Lucy as someone precious to him in the next chapter.
Chapter 325: It turns out that Yukino separated herself from the group because she feels that she will bring more misfortune on them if she stayed. Mirajane finds her and tells her otherwise.
Mirajane: "People all have their own reason for living. No matter how small it may be, even you have a purpose."
Chapter 332: When Atlas Flame realizes that Natsu is Igneel's adopted son he immediately sides with him since Igneel was his friend. Natsu even calls him Uncle.
Igneel is revealed to be the Flame Dragon King. Atlas Flame is a Fire Dragon. But its not loyalty to the Fire Dragon King that causes Atlas Flame to go through a Heel-Face Turn of sorts towards Natsu. It's that Igneel was his dear friend. It says a lot about the character and nature of the three dragons that raised the Dragon Slayers and how good they might have actually been.
Chapter 334: When Rogue is in shock over the idea that he's the one at fault for the dragon attack, Sting bursts onto the scene and calms Rogue down by taking what he knows of the situation incredibly lightly and insisting on sticking by Rogue's side. He manages to comfort Rogue without even realizing something was wrong with his friend.
Chapter 337: After Natsu destroys the gate, Future!Lucy fades out and appears to enter the afterlife. Who does she see first? Natsu and Happy. Present!Lucy sees her future self's diary fade out and realizes what happened...then goes over to Natsu and gives him a hug from behind.
Natsu: "Is something wrong, Lucy?"
Lucy: "No...not really... Just...thank you."
Future Rogue's last act before fading away is to tell Natsu to prevent Frosch's death in a year's time. In his last moments, all he wanted was to protect his old friend.
Chapter 338: Sting is having the time of his life with Lector and wants to find Natsu so they can enjoy some drinks in the hopes of striking a friendship. Orga even notes how cheerful the guy is.
Sting in this chapter deserves more of a mention. He actually apologizes to Yukino for the way he treated her in the past. Seeing him trying to change himself for the better is one big moment of heartwarming.
All of the guilds letting Yukino know that she is welcome in any of their guilds.
Yukino:(while crying) "Even if it's just a lie... I've never been happier..."
Chapter 339: Cobra tells us about how the outside world felt good and that he heard 'lots of voices...' including the voice of his best friend, Cuberos/Kinana's voice.
As an elderly Ultear is thinking about her insignificance in a world so large and the infinite possibilities that the world holds, she basks in the rays of the sun and notes that she feels them washing away her sins. She then states that for the first time, she felt glad that she was born and was finally able to forgive herself for her sins, happy and at peace with herself.
Chapter 340: The entire town of Magnolia pitched in to rebuild the original Fairy Tail guild hall, much to the joy of Makarov and the rest of the guild.
Chapter 341: Directly following the Grand Magic Games, when Lucy and the girls are in full furo scene at the newly-restored Fairy Tail hall, a repentant Flare Corona appears and tells Lucy how sorry she was for what she did to her during their match. Flare mentions that she left Raven Tail and has nowhere to go, but wanted to make amends before she leaves town. Cue a heartwarming scene of Lucy, Wendy, Lisanna, Mirajane, and Levy (who are all naked, btw) all hugging Flare and telling her that she's forgiven and is welcome at Fairy Tail.
Chapter 345.5: In a side story detailing the bet set up between Fairy Tail's Team A and Team B from the Grand Magic Games, it starts off as amusing when the B Team dishes out absurd and silly commands to Team A. Then we get to Cana and Wendy's side, and what did Wendy have to do? After playing "dress up" a bit, they both go to a Church where Cana used to reside at. There, it turns out all the children there are huge fans of Wendy and her feats in the Grand Magic Games. We also find out that Cana wanted to cheer up the orphans there as well as reminding Wendy that her family is Fairy Tail.
Chapter 353: Even after all the crap she pulled in the Grand Magic Games, Erza still tried to convince Minerva to not get involved in the world of the Dark Guilds because she doesn't want her to get corrupted by its darkness.
Chapter 358: The front of the chapter describes how during the seven years that the Tenrou Group was missing, Ichiya never stopped searching for them.
Warren on the cover page of Chapter 268 is described as doing something similar. Every day for seven years, without fail, he used his telepathy to call out the names of the missing Fairy Tail members, hoping that they would finally respond.
Chapter 367: Happy is distraught over leaving Natsu behind when he escaped from Tartaros' HQ. In response, Lucy gives him a hug and tells him he did a good job by bringing the hideout's location to the rest of Fairy Tail. Despite all the teasing between the two, they genuinely care about each other.
Chapter 376.5: In the midst of all the fanservice and imagine-spots disguised as Ship Tease, Juvia knits Gray a scarf for a gift and he blows it off. She later finds out that it's the anniversary of Ur's death and feels bad about it... but Gray remembers a time when Ur gave him a scarf and goes back to retrieve the gift. The next day, the two apologize to each other... and then Juvia gives him a customized Juvia body pillow as a follow-up gift.
Chapter 377.5: After delivering a bit of a beatdown on Moulin Rouge for impersonating a Fairy Tail member, Erza pats her on her head, and invites her to join Fairy Tail, since Rouge was an immigrant who could hardly get enough money to eat. Coupled with various hints from Mashima, it is heavily implied that this woman is Bisca. This is them really Heartwarming in Hindsight, since this means that not only did she surround herself by comrades at last, she also managed to start a family of her own thanks to Erza's invitation. D'aaaw.
Chapter 378.5/Side Story 2: Natsu and Lucy babysitting Asuka is a whole chapter's worth of "D'aaaawww...." moments, but the incident where Natsu helps Asuka get back her stolen lacrima from bandits after Asuka's teary breakdown is a stand-out.
Special mention should go to Aquarius for "playing the fountain" for Asuka's sake. While she is pretty annoyed at it, but coming from someone who has left Lucy in the lurch multiple times during battle "to go on a date", and is generally quite grumpy, it is quite heartwarming.
Thanks to Natsu's accuracy in shooting down the bandits, Lucy realizes that he let Asuka win their earlier target-shooting contest (after a whole lot of bluster about how he wouldn't take it easy on her).
Lucy:(blushing and smiling) "He definitely has a good side, huh..."
The whole story surrounding said lacrima. It was a prize from Bisca and Alzack's first job together. When Asuka fell ill at one point, they sold it to buy her medicine (this was around the time the Tenrou Group went missing and Fairy Tail dropped in the rankings), with the two citing they don't need it anymore as they have something much more precious to them. Ironically Asuka, with help from Natsu and Lucy, manages to buy it back.
Chapter 379: After Franmalth is defeated, Hades' soul is released, and offers up a mix between a warning and a heartwarming redemption: "It has only... just begun. Tartaros' true goal was not Face. Tell Makarov... this time, I shall release the light."
Chapter 381: The flashback tells us that Lisanna and Elfman went through all the trouble of learning Take Over Magic just to let Mirajane know that she is not alone.
Chapter 384: Despite Aquarius' hot-tempered and rude treatment of Lucy, we find out moments before Lucy breaks her Key to summon the Celestial Spirit King on her suggestion, that deep down she really cared for Lucy and that never being able to see her again makes her feel sad.
The fact that Silver's actions in the previous chapter were for the sole purpose of helping Gray past the trauma of Deliora (which explains his look of absolute panic when it looks like Gray is going to cast Iced Shell.)
The expression on Silver's face in the flashback, when he first learned Gray was still alive.
After the damage done to him in the fight, Silver drags himself up to embrace Gray. He even asks to stay in that position. Silver would end spending his last moments in the world holding his son.
We see the grave that Silver made for Gray and his mother, Mika, but Gray's is crossed out. Remember when we first see Silver in Chapter 353, it is almost immediately after the Grand Magic games, where he discovered Gray was still alive and he's visiting this grave. It's highly likely that Silver made the journey to Isvan just for that. After all, nothing screams "my son is alive" like crossing his name off of his grave.
The moment where, after seeing that Natsu was at a serious disavantage against Torafuza's Curse, Gajeel instantly yelled at him to grab Juvia and Lucy and find a way out there, showing off his Character Development.
Sure it was for air, but Levy giving Gajeel an Underwater Kiss was undeniably heartwarming. After being saved by him so many times, Levy returns the favor.
For props, immediately before it, when Gajeel was still fighting to stay conscious and Levy was nearing him, he saw a light approaching him.
And at last, after waking up immediately after the kiss and seeing Levy drowning and Torafuza rushing out to kill her, Gajeel proceeds to instantly turn into his Iron-Shadow Dragon Mode and deliver a massive blow to Torafuza's head, while yelling "Hands off!!".