That sounds very promising. We may just hear something tomorrow yet.
As for guesses? There's so many. What I want more than anything is birds of course, and then if not that, a revisit to Oceania with an animal pack..
There's been some very strong lineups suggested for a nocturnal pack and I would like that as well. But that's not saying that's what it will be. A drylands animal pack to balance out the wetlands pack is also a possibility, giving us more desert and grassland animals. An islands pack has also been gaining popularity that has a good lineup.
But for what it will be....any guesses are as good as mine.
What I don't think it will be: Rainforests. Now, it could be "forests" as a whole, but I feel like just Rainforests would be more of a tropical pack, like for spring or summer (of course, so do deserts lol) . I also don't think it will be a temperate/taiga pack as I'm suspecting that may be what we get in December. but of course, that's just my speculating, I could be off and it could be those.
And of course, it could be something that no one or very few people have even guessed the theme to. Just in this post I've brought up 7 pack themes and if you add in things like fully marine animals, Middle East (West Asia and North Africa), Petting Zoos and Mountains/Highlands, you're closing on a dozen different themes right there. I'm happy to be surprised with whatever it may be, because I'm just happy to get new content.