Don't know episode names so sorry for the summaries instead:
1. Batman and Ace episode. Surprising episode in general with the sudden inclusion of Terry, and adding a backstory for a character from a different series set in the future. I thought the lines between Terry and Amanda Waller were a bit lofty in bits but were very good and dramatic, not to mention the end between Batman and Ace. Thing is a tear jerker every time.
2. Wonder Woman turned into a pig. I thought the whole escapades of her as a pig were pretty nonsense but the Circe, Zatana, and Batman moments were great. Especially the ending where Circe just wanted Batman to sing lol.
3. Joker's live broadcast. Great episode with the live clock running down, multiple angles of the league fighting. Good ending too where Harley just lets a right hook full force on Batman's face. LOVE IT.
4. First episode of Unlimited, Green Lantern, Arrow, Supergirl, and Captain Atom team up. Great job introducing three very important characters to the last two seasons. Loved Supergirl and Green Lantern's interactions. They could have just made it boring and had Superman or Wonder Woman be her mentor, but its was soooooo touching and compelling to have Supergirl's mentor be Green Lantern.
5. Watchtower invasion by the ultimen . One of my personal favorites as well. Taking the ultimen clones, who were re imaginations of some lame characters to begin with, throwing them against the entirety of the JL! And Supergirl vs Supergirl all out -kissesfingertips- too good.
6. Amazo introduction...
7. Amazo return! my gawd. Talk about stakes.
8. Solomon Grundy return. Wow powerful and scary episode.
9. Episode with the Golden Age versions of the characters. Hilarious but interesting look at how things used to be and how messed up it was. I thought the twist/main ending was weak to be honest but I enjoyed the story and time period.
10. Taskforce X was a great episode too just because it was so different. Made even more so after the botched movie. This is the type of movie we were all hoping for with the Suicide Squad, why they went up against a Justice League level threat was beyond me.
And so many more awesome episodes and moments.
Not to mention the episode with Luthor being controlled by Braniac!!!!!