In the past, Elizabeth was never King Liones true daughter, but it is believed that he loved her as his own. This is proven when Elizabeth climbs onto a tree to get her father attention and he desperately tries to get her down from it despite not knowing how to climb. This cause him to fall fall and hurt himself. This shows that he cared for his daughter very much, even if they are not blood related.
When Elizabeth offers herself for Meliodas safety in the first chapter, she kept on crying saying that Meliodas was being too kind to someone he doesn't know. Something that Meliodas completely disregarded as he protected and saved her from Twigo. The when Meliodas offer Elizabeth to travel with him, she happily accept.
When the town folks were upset at a young boy for pulling a prank on a Holy Knights for making fun of their drink making skill. The village leader was the only one who stood up for him, saying that the boy protected their pride which not of them had done and worked together to remove the holy sword to free their water. Despite not moving the sword at all, they show that they cared for one another and worked together to return their pride.
After seeing Meliodas again for the past ten years, Diane was overjoyed and started to cuddle him, showing that she cares for and loves Meliodas.
Elizabeth became depressed after Meliodas got injured and the doctor that was supposed to help him was forced to kill Meliodas instead. She blamed herself for the whole ordeal because she made Meliodas and the doctor get involved. However, Meliodas told her that she should stay strong and even told her that even if she died, he will continued to stop the Holy Knights in her place.
After Elizabeth saved Meliodas and Diane from Ruin illusion, Meliodas went to her and said that he accepted her will and went on to fight Ruin. During the fight, Meliodas defeated Ruin and said that there is no way for him to escape since he hurt someone important to him, and that was his sin.
When the stone up Ban was left behind by King, the spirit of Elaine came to Ban and set him free with a kiss. This shows that Elaine still loved Ban even in death.
Despite leaving her alone for the past seven hundred years, Elaine still shown to believe in King and told him to protect Ban.
Even in death, Ban still swore to make Elaine his which made her happy.
After being (temporarily)shrunk down to normal human size giant Diane is very keen to gain a affections of her once sided crush Meliodas. After this is played for laughs as she asks him to grope her like he does Elizabeth, he declines, stating that he'd never do that to her because he cares too much, as she starts to tear up, clearly upset, he tries to cheer her up by rubbing the top of her head, something he could never have done previously and her appreciation is clear to see.
Even after hearing Meliodas said that he doesn't fondle anyone important to him, Elizabeth stated that she will still believe in Meliodas no matter how he sees her.
In Chapter 39, When Cain ask again if Meliodas really destroy Danafor to which he told him he didn't betray anyone, Cain then start crying and hugs Meliodas, being glad that he didn't betray anyone they care about.
As Elizabeth was being forced to being taking back to the kingdom by her sister, the beaten up Meliodas stand up and stand between them and even stating that he will protect Elizabeth with his life, showing that Meliodas seem to care for Elizabeth a lot.
It was shown again when Meliodas broken sword was stolen, Meliodas didn't seem to care much about it and also reveal that if Elizabeth was alright, then he is happy which made Elizabeth blush heavy.
In Chapter 46, when Veronica sacrificed herself to save Elizabeth from Geera's attack, she stated that despite them being not blood related, she still loves Elizabeth as a sister.
During their training, Ban revealed to King that he is planning on getting a magical item from Liones that could speak with a Goddess and ask them to revive Elaine. This shows that Ban really want Elaine back if he is going through the trouble to ask for a deity help.
In the same chapter, King mention that Meliodas could be a demon himself, but Ban grew anger and was threatening to bust King teeth out for saying that. Ban then went on saying that Meliodas and Elaine were the only two people to accept him for who he is which no one had ever done. He even think that Melioas is too kind to be a demon which shock King. This shows that Ban respect Meliodas friendship.
Despite being a cruel woman, Geera shows a lot of love toward her younger brother, Zeal as she kill his bullies and sworn to do everything she can to make him happy.
She even makes a Heel-Face Turn and helps Diane after the latter protected Zeal. Hell, Diane ruining her chances to escape for saving a child she doesn't even know (when she previously had said she didn't care about humans) is this. And Zeal being the sweetest little brother ever.
When Gowther saved Pelio from a attack from the Armor Giant, it shows that despite being emotionless, he shows a lot of care toward his young master who saved him in the past.
While Diane was wondering if Meliodas would ever make a upset face if she was kidnap like Elizabeth, King told her that he would definitely come for her even if he does it alone which made Diane happy, but wonder if he does it to cheer her up.
As Diane was fighting against Dreyfus she was injury heavily and could barely fight, but all she care about was to save Elizabeth who she said was her friend.
To note out that at first Diane didn't like Elizabeth because she was close to Meliodas, but doing the series, she grew to like and respect Elizabeth as a friend of her which is rare for Diane since she think nothing of all men beside Meliodas and dislike any female that are close to Meliodas. It shows that Diane truly cares for Elizabeth.
Guilthunder being finally able to help Meliodas after the latter killed the chimera keeping Margaret hostage. He even cries while he thanks Meliodas and calls him his hero.
Arthur's cheerful hero worship for Meliodas. Especially because is obvious that Merlin had a hand in it.
King Bartha has several of this:
His reunion with Elizabeth. Pure fatherly love.
He doesn't only rescued Threader, he gave him a name, taught him how to live in society and give him the best job Threader could ask for. Threader's Undying Loyalty is obvious but we see how much Bartha cares about him when Threader risks his live trying to open the charmed door and Bartha begs him to stop before he kills himself.
His friendship with Arthur is very cute too. The young man remembers him fondly and goes all the way to his kingdom to rescue him.
Dreyfus arriving in the nick of time to help his son (who is obviously happy to see him again) to fight Hendricksen
This is more a Tear Jerker, but Ban desire to bring Elaine back to any cost proves his utter devotion to her. The Tear Jerker part is what he has to do to resurrect her and he obviously is broken for it but he'll do it anyway.
Gustav showing his concern for his sister despite being previously an asshole to her. He even begs Ban not kill her. Props to Ban too for really find a way to recover Jericho alive.
When Merlin's not being shady and doing things for the lulz, she's pretty much this.
After all the insanity dies down thanks to Hendricksen's defeat, King encounters Diane, who has been shrunken down to human size with some magic pills. She then asks him if he'd like to spend some time with her. He declines at first, saying he doesn't want to be a third wheel since he figures she wants to use the opportunity to hang out with her crush, Meliodas. She then makes it clear that Meliodas won't be there, and she wants to go out with him.