Justice (comics)/Heartwarming

• When Superman saves Zatanna from the vacuum of space and revives her with CPR.

Zatanna: Sknaht.
Superman: "Sknaht"?
Zatanna: (with tears in her eyes) I meant, thanks.

• When Black Manta orders his minions to execute Aquaman's infant son, only for them to stand together and defy him.
• Captain Marvel coming to Superman's aid definitely counts, particularly once you consider that their last - and arguably most famous - major encounter was in Kingdom Come, where the two fought one another. The scene is even a mirror of the Kingdom Come moment, but instead of the Captain standing over Superman, ready to fight, he extends his hand to a man who could really use it.
• Jean Loring sat next to a fatally wounded Ray Palmer. She initially wanted her to quit being a superhero, but more than ever she wants him to come back to her. Much more heartwarming, despite what happens between them.