The castaways becoming a family. They may have been in Hell, but they weren't totally deprived of light.
When the Queens and Wests learn their loved ones are coming home. Especially Mr Allen's reaction, who took the loss of his son so bad he almost committed suicide. And the Tears of Joy flow again when Barry visits him.
The guards bend the rules for Henry to allow him to hug his son for the first time even though his visits arent conjugal.
Astra's utter relief and joy to learn Kara survived Krypton's destruction.
Slade escaping Waller and finding his way back to his kids. They all glomp him — even Kal, who was barely a toddler the last time they interacted, is happy to see him again, to the point of calling Slade 'Papa' just as he did when he was a baby.
Even if it's a mark of how screwed up the timeline was, Batman never appeared since Martha and Thomas never were shot in the alley. Just for once, Bruce Wayne got to grow up with his parents.
Dante awkwardly comforting Barry right after Zoom psychologically tortured the speedster. He really doesn't know what to say, he just can be there... and sometimes, that's all someone needs.
After Barry and Dante are rescued from Zoom's prison, Dante and Cisco begin reconciling once Dante reaffirms to Cisco that he doesn't blame him for what Zoom did and that he'd like to have a stronger relationship with his brother. Cisco agrees to reconciliation, and the two begin to mend their broken relationship.