Whenever Stampy starts cooing over his pets... or really, whatever animal he comes across.
Every Love Garden sequence, as Stampy gives a shout-out to people who have supported him throughout his videos, e.g. his friends and mainly fans who have made content dedicated to him. It's nice to know that he appreciates his fan base and their support so much.
The latter half of Episode 500, "Memories", features Stampy giving a thank-you speech for the support he has received.
Any time Stampy shows explicit concern towards his friends and Helpers (and even NPCs) and goes out of his way to do nice things for them, especially with HTT's accusations of tyranny towards him in Episode 526, "Saving the World". It goes to show and serve as a reminder that that despite everything, Stampy shows genuine friendship towards them and cares about them.
On the topic of NPCs, there's Harrison and Harriet. Both of them used to be zombie villagers before coming across the Lovely World, at which point Stampy dropped everything in order to cure them. Even after that, Stampy went out of his way to make sure they would have a place to stay, building Harrison's Hangout and Harriet's Hut. They even have chests under the Christmas tree every year!
Episode-specific
In Episode 79, "Giant Fish Bowl", Stampy jokes about Helper Frog Angel sleeping through the entire episode, only to immediately apologize and clarify that he's only joking in case she's watching the video.
Not only does he immediately apologize for killing HTT when it seems that he was Good All Along, but gives him a cake when Target reveals that the only thing he has to eat are spider eyes and rotten flesh. He's even the one to ask if there's anything he can do to bring Hit The Target back from the dead, and offers to take him on a tour of his Lovely World once he's revived.
His little monologue as he heads back to the Overworld is also incredibly sweet; it's evident from the tone of his voice that he is absolutely elated to have Hit The Target back as a friend.
Stampy: I'm in such a good mood now — and go away, Ghast! I don't care about you, I don't care about your fireballs, I got a new best friend! [...] Zombie pigmen, I don't care about you because Hit The Target's friendly!
And it's not just Helpers, but NPCs as well. In Episode 118, "Flower Power", Stampy explicitly cites that he's trying to win the tournament for the eponymous minigame so that he can give his constructs, Henry and Hilda, a room, so that they weren't stuck on his balcony and wandering his house, respectively.
Stampy: I'm not winning for my sake, I'm doing it for my family.
Most of the stories in Episode 243, "Ghost Stories", are rather bleak, but the story of the ghost dogs is quite cute. All of Stampy's dead dogs rise from their graves and dance in the clubhouse every night as ghosts, throwing a party and just having fun together. Given some of the awful ways they died, they more than deserve that.
Sqaishey showing concern to Stampy in the comments section of Episode 355, "Friends and Foes", after Veeva Dash's betrayal. Considering Stampy's hesitation to trust William Beaver in the episode, this seems like some much-needed reassurance for him.
While Played for Laughs, Fizzy's birthday suprise in Episode 393, "Fizzy Elephant", is surprisingly thoughtful. At this point in time, he knew little to nothing about Stampy and the Helpers (when asked about Sqaishey, he thought they were some sort of pet), but still took the time to prepare a pretty elaborate celebration when he thought it was Stampy's birthday.
Episode 454 ("Polly's House") and 455 ("Revenge") are dedicated to helping Polly build a replica of her stable from the North Pole and seeking justice for her when her house gets destroyed immediately after they finish construction.
The Lunar Friends' art piece in Episode 484, "Mental Block". Entitled 'Home', it's a statue of the two of them with the room split in half; one side is stylized to look like the moon, while the other is stylized to look like the Lovely World, reflecting that they now consider both places to be their home. Made doubly heartwarming when Stampy reveals seconds later that he had been worried that the Lunar Friends weren't happy in the Lovely World — they might not interact with Stampy as much as the Helpers do, but he still cares about them deeply.
A minor example, but when Fizzy sees Stampy and Hit The Target together in Episode 526, "Saving the World", he immediately jumps off of his sheep roller-coaster and runs towards them to make sure Stampy is okay. Not only that, but when Stampy is forced to claim that Hit The Target has secretly been Good All Along, Fizzy is ecstatic, and starts jumping up and down in celebration. He may be a bit of a Cloud Cuckoo Lander, but at the end of the day he just wants everyone to get along.
At the end of Episode 542, "Hero Helpers", Stampy adds the new Helpers to the Love Garden to commemorate their rescue mission.
After the Jump Scare in What Is This?, one of the scary movies in Episode 564, "Scary Movies", Fizzy runs out of the theater. When the film ends, Stampy immediately heads out to check on him, taking the time to calm him down and reassure him that it was just a movie.
Despite the fact that he knew Fizzy was guilty of killing William's chicken, Stampy still acts as his defendant in order to ensure a fair trial in Episode 653, "Trial". He even takes the time to remind the judge (Polly) that Fizzy is a hero that has saved the SLW over and over again, and tells Fizzy just how much he means to him.
Stampy: I hope you won't mind me saying this Fizzy, but you are my friend, and I love you.
All three of the Halloween stories from the Halloween Episode "Terror Trio" (Episode 657) classify as this: the headless Ghost Pirate and the Ghast without a body teaming up to explore the SLW; Tutankhamun, the Sphinx and the Mummy playing Hide and Seek in the pyramid the 'Temple Trap' minigame takes place in; and Star-Crossed Lovers Sol and Mani reuniting on Halloween night to create a total eclipse.
In Episode 698, "Locomotive", Stampy accidentally ends up on the railing of the bridge he and Polly are building on, and is unable to get back on due to the positions of certain blocks. So when he sees that a zombie has spawned a few blocks away from Polly (who is still on the bridge and weak after a creeper explosion), what does he do? Immediately tell her to lure the zombie to the railing so he can take it out and keep her safe, while urging her to be careful the whole time.
Episode 700, "Tragic Day", is significantly sadder than most 100-episode specials, but there are a few cute moments.
After finding the dog that HTT's dog army was cloned from, Stampy shows her no ill will, understanding that it wasn't her fault. He decides to adopt her and names her Secret, after the Secret Base where he found her.
The Helpers' surprises are rather sweet as well — Polly makes a noteblock version of "Twinkle Twinkle Little Star" (because Stampy is their star), William makes a minigame for him, and Fizzy makes a cake shop (albeit one that requires three netherite for a cake) and puts on an elaborate firework show.
Episode 701, "Remembering": The entire episode is spent building memorials for Fluffy, Bengy, and Corey (the latter two having died in the previous episode and Fluffy having been mistaken for dead) in order to remember them. Stampy's speech about how he wants the park to honor the dogs themselves instead of the battle they fell in is rather touching.
Stampy: It is sad when something or someone dies, and there's no way to get around that sadness. And that sadness, you know, might always be with you. But it will fade, you know. It will, you know, lessen over time, and eventually you're going to be focusing much more on the fact that you had so many good times with whoever it is rather than, you know, the fact that they're no longer with you. And that's what I want this park to represent! I want this to be a place where we think back on all the good times that we had with those dogs rather than focusing on the fact that they're sadly no longer with us.
Episode 703, "Stampy Fails At Redstone": In a mixture of heartwarming and funny, the Helpers build a cage around Luna to protect her, making it out of glass so that she can still watch them build.
Episode 705, "Chaos And Cake":
Secret is finally comfortable spending the night in the Doghouse with the other dogs — and after being isolated for who knows how long, she more than deserves it.
Similar to the example with Frog Angel above, Stampy assures Ank that he loves the F1 racing car he got him for Christmas years ago in case he was watching the video and misinterpreted Stampy's statement about moving it to the museum. He says something similar in case Longbow is watching during Episode 707, "Collecting History", when he moves the giraffe he built on the S.S. Stumpy.
Episode 707, "Collecting History": Aside from a few concerning moments, the entire episode is just a sweet trip down memory lane, with Stampy discussing SLW history and talking about Helpers that haven't been mentioned in years. For long-time viewers, it can definitely bring about warm and fuzzy feelings.
Episode 709, "New Caves": Stampy's utter delight at discovering all the aspects of the new update, from dripstone to the axolotls (which Stampy pronounces as "axowottles").
Episode 719, "I Won": Fluffy is revealed to have survived the battle in "Tragic Day". Not only is this a major victory for long-time fans and those who considered Fluffy their favorite dog, but Stampy is ecstatic as well, calling this "the best day I've ever had in my Lovely World". Also, imagine how happy the dogs must've been to see one of them has survived, as well as how happy Fluffy must have been to return home and reunite with everyone.
Episode 727, "A New Dog", has several of these moments:
A small double whammy first — Fizzy and Polly finding a stray dog/wolf in the middle of the episode and very enthusiastically asking if Stampy wants to tame it, while Stampy turns down the offer (because he has "more than enough dogs") and lets Fizzy tame it and name it. So yeah, the 'caring for each other' thing is mutual between Stampy and his Helpers.
At the end of the episode, Fizzy asks Stampy if he can name the game they were building that episode 'Mattress Man' after the dog he tamed earlier in the episode. Stampy obliges, though with some joking, light-hearted exasperation that his Helpers were taking control of the Lovely World and that he was just "on for the ride", and even makes Mattress Man the dog the mascot of the minigame.
Episode 729, "Dribbly Dream House", is filled with this, as it features Stampy, William and Fizzy revamping the old waterfall in front of Stampy's balcony to make a permanent home for Dottle the axolotl.
Episode 733, "Christmas Invasion", ends with one. When HTT gloats that he's won and taken over the World after nuking Stampy's room to shreds and redecorating it for himself and Veeva Dash (not that Stampy knew of the latter part at the time), Stampy refutes this and trash-talks him, saying that the reason the Lovely World is 'lovely' is not due to the builds themselves, but because of The Power of Friendship and the memories associated with the World.
Episode 746, "My Big Build": The revelation that Stampy cut off the newly-built path leading down to the dock area in front of Lucky's grave.
Stampy: Some of you may remember that Lucky died in my first battle against HitTheTarget, and one of the very important things that I made sure was that I didn't disturb Lucky's grave, [the path] only kinda goes up to here– (gestures to the end of the path, a few blocks away from the gravesite) And if anything, it means now people are gonna come down to this area more and walk down the path and be able to visit it a bit more, so I think this is hopefully gonna be a good thing for Lucky's memory. But yeah, shout-out to everyone who remembers those old episodes and– remembers Lucky! Lucky was an awesome dog.
Episode 823, "Thanks For Watching":
When Hit The Target threatens Barnaby's life and Stampy decides to give up his World for that, while somber, also is extremely heartwarming in that when it comes down to it, Stampy cares about his friends and his loved ones deeply and would rather have them be okay than keep his physical Lovely World.
Stampy's final speech, claiming that even though it's over, he'll always have the memories of the things they did and the friends they made, and for the final time, thanks the audience.
The final montage, where Stampy goes around his Lovely World, collecting all the friends and allies he made as they all walk off into the distance. To make this extra sweet, he collects characters that were generally Out of Focus throughout the series, including Fred the Enderman, the Villagers, and even Harry the horse. He never forgot them.
And in a blink-if-you-miss-it moment in the final shot, Veeva Dash comes to join the group in leaving. Learning that Veeva Dash was trying to help Stampy in the end by warning him of Hit The Target's schemes and later using an invisibility potion to save him, it tugs at our heartstrings in that in the end, when it came down to it, Veeva Dash changed for the better and chose to be good.
Miscellaneous
The fact that Stampy still believes in Veeva Dash after all she did, even offering her a spot as a Helper again after their Enemy Mine moment in Episode 624, "Helpless" (she refuses, but it's the thought that counts). She may have betrayed Stampy, but he still sees her as a friend, not an enemy.
", after Veeva Dash's betrayal. Considering Stampy's hesitation to trust William Beaver in the episode, this seems like some much-needed reassurance for him.Sqaishey Quack: I had no idea!!!!! [...] Don't worry stamps, you real friends will never betray you! :)