Alexa trading places with Diana so she can compete. Especially Diana's huge smile and hug when she learns of Alexa's plan.
Diana revealing herself at the competition. You'd expect Hippolyta to be angry, maybe even turn her down completely. But she doesn't. She takes the tiara off her own head and gives her full permission to Diana to go.
Hippolyta: I have no doubt you will serve us well, my daughter.
Basically, any time Steve talks with Diana, if it's not a Funny Moment. Notable points are when he tells her that he chose saving her over stopping Ares because he cares about her, and when he starts telling her about himself on the plane (although that was partially brought on his foot being stuck in the Lasso of Truth). Not to mention the Big Damn Kiss at the end.
Diana teaching a little girl how to swordfight, after noticing that the girl is sad because boys won't let her play with them.
Artemis saying goodbye to Alexa and calling her "sister". After an entire movie of disparaging Alexa's pacifistic, bibliophile tendencies, they save the zombified Amazons from being forced to kill their sisters in combat and stand together to fight Ares army. Crosses over into tearjerker territory.
And although it turns into a (mild) Funny Moment, Artemis' final scene is her trying to find the patience to read books; Alexa, in her last scene, had shown Amazonian courage for the first (and last) time ever, making this feel like Artemis is returning the favor - both are looking from the other's perspective at last.
Villains though they may be, it seems as though Persephone and Ares were genuinely in love. The viewer is teased with a moment where it looks as if Ares may reveal he was just using her to escape prison, but it turns out they appear to be in love for real. Persephone even says so when about to fight Hippolyta.
