So last night's episode of Gotham was amazing but not as good as I thought it to be. However, there were still some easter eggs and references in that episode.
I'll carve your face off
Joker literally cuts his face of in the comics. This is a direct reference to that.
OK i could not find the image for this one. I'm the only one who spotted this easter egg. Ok in the beginning of the episode with Gallavan's sister, there was a clown graffiti art. Somebody put HAHAHAHAHAHA on it. Nobody else saw this but me.
That's it the other's aren't very good easter eggs.