First up we have some alien horses, which may have been used for Kirk and McCoy's get away, had Kirk not shot it. In the end the polarilla from from the first film was reused, with a different finish.
Here's a design for a smaller Nibiru native:
And finally (continuing after the jump), several concepts for the big fish that Scotty sees from the birdge window/viewscreen:
Source: Alfonso De La Torre's Facebook, via Comic Book Movie.
For more on the production design of the nuTrek films, there is an excellent book covering the first film, Star Trek: The Art of the Film. Unfortunately there has been no equivalent for Into Darkness, but you can find links to my coverage of lots of other concept art and other behind-the-scenes stuff on my Into Darkness guide page.