We've already seen the LexCorp logo featured prominently in the film, that one's impossible to miss. We also know about the Wayne Enterprises logo appearing on a satellite, and the extremely weak tease for Cyborg. Slashfilm has pulled together a few more which are pretty cool, even if they don't amount to squat.
The first almost nobody but the most die-hard DC fan will notice or care about, and it involves a very quick glimpse of a billboard for Blaze Comics, which is the fictional publisher of comics based on the time traveling hero, Booster Gold. Does that mean we'll see Booster Gold any time soon? Um, probably not, although I'd kill to see a cinematic version of Keith Giffen and J.M. DeMatteis' Justice League run from the 1980s.
The next one has some serious legs under it and could lead to something important down the line. When Superman discovers the Kryptonian vessel, around the time he first encounters Lois Lane, he runs across a few cryo-stasis pods. One of them contains the remains of what is likely a dead Kryptonian, but another of the pods was empty. While this could mean nothing, the evasive nature of producer Deborah Snyder's answer when asked about it leaves the door open to speculation...
Snyder: "You know what’s interesting, and I don’t know and I’m not going to say what it means or anything, but the one thing if you look closely when Henry’s going through the Fortress of Solitude there’s an empty… you know all the bodies… the pods? There’s an empty pod. I’m not going to say what, or if, it means anything but there is an empty pod there."
When asked directly if the pod contained Supergirl, she said...
Snyder: ”No. [Laughs] I’m not going to say anything but, it’s a thing.”
So why Supergirl? In the film's prequel comic, it shows a fight between a murderous stowaway named Dev-Em and Kara Zor-El aka Supergirl. After Dev-Em killed a number of the ship's crew, he and Kara were the only two alive when the vessel crashed, but it's unclear whose corpse that was Superman found, and what happened to the other. Either we just got a major hint to the sequel's villain, or we're looking at another Kryptonian hero living undercover on Earth.
The last one may be the best evidence yet that Warner Bros. is pretending that Green Lantern film never happened. One of the final scenes involved Superman having a conversation with a military general played by Harry Lennix. Accompanying the general was a young officer played by Christina Wren, who comments that she thinks Superman is "hot". A look at her tag shows that her name is Carrie Ferris, and is probably a reimagining of Carol Ferris, who we just saw portrayed by Blake Lively in Green Lantern. She also happens to be the super-powered character Star Sapphire, who has been both a hero and a villain.
Man of Steel has proven to be as divisive as expected, but I think most would say it at least has laid a solid foundation for a larger cinematic universe. You check out my review of the film here, as well as Julian Lytle's opposing view here.