Marvel's two teenage-centric television shows, Runaways and Cloak and Dagger, focus on characters with dysfunctional family lives. The reason the Runaways band together is to stop their parents, who are supervillains. Meanwhile in Cloak and Dagger, Tandy has a dead father and a drug addicted mother, and Ty comes from a loving family that's haunted by the memory of his older brother being murdered by a cop. Despite this, the heroic teens of both shows relate to each other in surprisingly healthy, functional ways, giving fans amazing found families to watch.
Runaways
At the beginning of Runaways, the six characters have been largely absent from each other's lives since the death of Amy a couple of years ago, the notable exception being adopted sisters Gert and Molly. They end up hanging out and subsequently learning of their parents' crimes, and from that moment, they're a sworn team. Their individual relationships aren't perfect right away. For instance, Gert is skeptical of Karolina, in part because she has feelings for Chase. However, Chase has feelings for Karolina, but she likes Nico, who briefly dates Alex. Despite this, they're quick to stick with each other and offer support.
The first main conflict between them comes when Nico finds out that Alex was lying about what he knew in regards to Amy's death. Alex lashes out and accuses Nico of being unapproachable, and Nico snaps back, ending their budding relationship. Soon after, Karolina confesses her feelings to Nico, and the two start a relationship, but aside from a suggestion that the others leave Karolina to fend for herself when she's captured by her father, Alex doesn't get angry about this. As the next two seasons progress, Alex and Nico repair and strengthen their friendship, to the point where they're probably each other's best friends.
The romantic bond between Nico and Karolina is, in addition to being an improvement on the comics, one of the foundations of the entire show. The two girls couldn't be more different; Nico is a sullen, individualistic goth and Wiccan, while Karolina is a sunshiney California girl irrevocably influenced by her mother's cult. However, they're quick to restart their friendship, and it doesn't take Karolina long to express her interest to Nico. Especially given Karolina's religious background, this coming out shows great trust, and it's rewarded by Nico reciprocating her interest.
Their relationship isn't perfect, as their bond is tested by Karolina's alien father, the arrival of Karolina's shapeshifting suitor, the struggle with Morgan and Nico's overwhelming magical abilities. However, even when they're fighting, they clearly care about and protect each other.
Gert and Chase also begin a romantic relationship in the same episode as Nico and Karolina, and they have even more ups and downs. Gert's anxiety shapes her arc in Season 2, while Chase deals with being gaslit into forgiving his abusive father. They spend the majority of Season 3 broken up; however, they still care about each other, so when Gert is killed in the fight with Morgan, Chase spends several years inventing time travel so he can prevent her death and the group's split up.
The platonic bonds among the Runaways are important too. Molly, who's younger than the others, is the group's metaphorical little sister and Gert's literal sister. In fact, Chase shifts from being romantically interested in Karolina to being a caring, brotherly figure toward her. Gert and Karolina eventually bond too, explicitly over the desire to help others. Xavin even ends up developing their strongest friendship with Molly, who teaches them about normal Earth things and feelings.
Cloak and Dagger
While their group is smaller, the young heroes of Cloak and Dagger still deliver a loving and mature depiction of found family. Tandy and Ty mostly interact with each other and Ty's on-off girlfriend, Evita. As children, Ty saved Tandy from drowning, but they didn't see each other again until they were teenagers and the Lightforce/Darkforce powers they'd been imbued with manifest.
They're literally two halves of a cosmic bond, the Divine Pairing, but the narrative doesn't use that as a way to force them together. Instead, they spend most of the show getting to know each other and bonding in a relatively platonic way, learning each other's secrets and supporting each other, and it's only in the last scenes -- and their subsequent guest appearance on Runaways -- that they're shown to be a couple.
The Ty and Evita relationship is handled with remarkable maturity too. They're just a cute high school couple, and they're as normal as a superpowered boy and a Voodoo priestess in training can be. After hiding from the law and ghosting Evita, Ty returns, and Evita's reasonably upset but also understanding. Furthermore, she doesn't blame Ty and Tandy for her Aunt Chantelle's murder at the hands of their current enemy; instead, she assists them in the fight against said enemy and ends her relationship with Ty amicably.
When Tandy and Ty show up in the Runaways' lives, the eight of them quickly form a supergroup and help each other fight. They all get along, and even Tandy's initial wariness of Nico blossoms into trust and a burgeoning friendship. They continue to interact with each other in surprisingly mature, understanding ways. In general, Marvel's adult characters could stand to learn some lessons about friendship, teamwork and healthy romances from Cloak, Dagger and the Runaways because they've mastered supporting each other and their team better than most adults.