If I were to guess, we might get another animal to go in the "more animals and pets" category. This could make way for Plopper (aka Spider-pig) and Mr. Teeney.
Also there is unreleased content to consider. The Olmec head has been in the game's code for a while now and they are finally releasing it now. (I believe it was originally going to come out in 2012) There are some other items that have been sitting around on Tapped Out Inc's hard drives that will be released. I'll put a few down here....
Satan's Anvil
http://simpsonswiki.com/w/images/0/0f/Tapped_Out_Satan%27s_Anvil.png
Mayan Marge
http://tstonews.com/imgs/menu/marge_mayan_menu.png
Camping Tent
http://simpsonswiki.com/w/images/9/9e/Tapped_Out_Camping_Tent.png
Sit-n-Rotate
http://simpsonswiki.com/w/images/thumb/8/8f/Sit-N-Rotate_Tapped_Out.png/200px-Sit-N-Rotate_Tapped_Out.png
