Ok, we already have run into all of the above in some form or another. Here is the past and future possibilities for the upcoming 115 horrors.
Humans - Obviously, this is nothing new. We have a miriad of examples that have shown up through the maps. These include Zombies, Panzers, the Pentagon Thief, Astronauts, George A. Romero, Shriekers and Napalm Zombies.
Animals - Beginning with Fluffy, the original hellhound, animals have also been a staple to the Zombies dialouge. Others have included the Nova 6 Crawlers, which also could have been considered to be human at one point, Monkeys, as well as the DOA Gorilla, and the flying bugs in SoE.
Plants - Plant life has rarely been used in the series. Der Eisendrache utilizes a plant for a small EE and SoE has the Harvest Plants that produce the wonder weapon part and other drops that help you along the way.
Do to the last entry not getting much face time in the past leads me to believe that we will see something significant with plant life in this upcoming map. Could it be a Venus Fly Trap like 115 horror? This is possible, the Giant map's EE is "The Flytrap" after all. Then again, there is other ways to catch a fly. Speculations have added the possibility of a Giant Spider. Either way, I think Treyarch has fully covered the human aspect of zombies to such a point that the other two categories have a greater chance in being utilized. Personally, I am fond of a Jumanji type vine system being annoying and overbearing on progressions in the map.
What are your Ideas???