It defintely seems like we're getting Happy Haunts, but I too am holding out hope that we get a second occult pack this year.
Based on the hints that have been around lately, a music or band themed pack also seems quite probable.
So as far as realistic guesses go, I'm going to say we're getting
- Happy Haunts
- Band/Music based pack.
Now, as for content I'd love to have before we transition into Sims 5, that's a little bit more hopeful/dreamy.
- Superheroes (One of my absolute dream packs)
- Gods or Maybe Elementals
- Demons and Angels
- Faeries
- Werewolves
- Some kind of pack that introduces Zoos.
- Some kind of pack that adds more to teenagers
- Some kind of pack (or even just a patch) that adds more to romance
World Types I'd love see
- Scottish Highlands
- Nordic Inspired World
- Beachside town (not like Sulani where it's a tropical paradise. Something more like Virginia Beach in real life.)
While they aren't dream packs of mine, I defintely wouldn't mind a generations pack or a pack that includes farming. I don't think I want a pack entirely centered around farming as I wouldn't use that feature much at all, but a country themed pack that features farming? I'd be cool with that, so long as they added other things too. Like maybe a mechanical bull your Sims can ride, hoe-down/rodeo, line dancing, etc.