In March 2016 Batman v Superman came out, we all watched the epic fight scenes between Batman and Superman and Doomsday with Wonder Woman too! But, apart from the fight scenes, there might've been some Easter Eggs you've might've missed, so if your about to go to Batman v Superman, read this article to get the details
No. 1 - The Flash
While Bruce is having a nightmare, he is interrupted by a time traveller who warns him that Lois Lane is something important for a future event, and that he has to find the others, possibly referencing the Justice League, he also says he was right about him. "Bruce, you were right about him, Louis is the key, find the others" -The Flash now, also in this scene we can see a glimpse of The Flash's costume, it seems like it has a helmet or some sort, and looked like it had metal armour on it, could it be from Bruce tech? We don't know, it was mentioned that, that scene would be resolved in a future film, potentially Justice League or The Flash (film). Another scene shows Diana Prince, looking at some metahuman files from Lex Luthors hard drive that Bruce emailed her
No. 2 -Aquaman
On one of those files, Aquaman is seen throwing his spear at the camera during an underwater investigation.
No. 3 - Cyborg
Another video shows footage of STAR Lab's Dr Silas Stone, experimenting on something, and we see a man (Victor Stone) in the background and shows his body and that his legs have been torn off somehow (possibly will be shown in the Cyborg or Justice League film) then a box (possibly the Motherbox) is shown hovering and then quickly merges with Victor's body and becomes Cyborg.