1) "Revenge Is Gonna Be Mine" -- imo this is pretty underrated. Captain Hook sure can sing. And his drinking buddies are just like "huh, we're all singing... we needs choreo!"
2) "Wicked Always Wins" -- I got awesome Defying Gravity vibes from this, which was probably intentional. Also, Rebecca Mader's light, clear voice suits the melody perfectly.
3) "Charmings vs. Evil Queen" -- I just love that sing-off!
4) "Love Doesn't Stand a Chance" -- I don't find the song itself particularly interesting, but the screenplay of the Evil Queen strolling into people's homes and mildly inconveniencing them by flipping tables and breaking axes is hilarious.
5) "Powerful Magic" -- This is not a terrible song and I'm not trying to hate on Snowing. But it's also the only hero song back in the Enchanted Forest, and villain songs are undeniably better than hero songs any day.
6) Emma's Theme -- It's not that I don't like the lyrics or vocals...it's just that the song's placement makes it the cheesiest song in this entire episode.
Just singing at the Black Fairy made her go away? It was that easy? She's gone, permanently? Wait, nope, she'll be back, otherwise we wouldn't have a season finale. Well, did it at least temporarily disable that curse? Uh, nope, it's still intact and right on schedule! Basically all that "power of song" did was undo Regina's time-freezing potion, which could have been undone with true love's kiss, right?
TLDR: Villains get the best songs.