3. Spider-Man
Marvel haven't cast the new Spider-Man yet, so an appearance from Peter Parker is probably unlikely. However, that shawarma tag was shot days before the release of The Avengers, so he could still find his way into the sequel if they're quick. Alternatively, it's not exactly hard to make a CGI Spidey (with the mask on) swinging through New York City in footage being watched by someone like Tony Stark, but even a mention would be huge. After all, Spider-Man's appearance in Captain America: Civil War is extremely significant for both Marvel and Sony, and any sort of reference to the wall-crawler here will build anticipation and get everyone talking. There's definitely a chance that fans will be kept waiting until 2016 to see the return of Spidey and his debut in the Marvel Cinematic Universe, but don't be too shocked to see him referenced in at least some way in the sequel.