In terms of very early spec with one actual announcement yet no clues from the usual suspects...
Evil Dead Rise - It was planned for this year, they were in the process of building it, and then it got scrapped. Thankfully it sounds like there was no falling out between rights holders and Uni, it was most likely due to the film being pushed back to 2023. There's honestly a very good chance it could return!
Some sort of UCM House - This is a well that just keeps giving and giving, and with Legends Collide kicking butt, I'd say it's as close to a given that we'll be getting another UCM House. The fun part is, who and/or whom? Personally, let Dracula (and his Brides) take a rest as they've been in all three houses so far. I'm fine with Frankenstein's Monsters, Wolf-Man and Mummy taking a break, too. That still leaves us with very fun options! I would honestly love a Creature from the Black Lagoon house, but I also think a great choice would be Phantom of the Opera in some fashion. Be it a retelling, remake, original spin, the creative team can take this in so many directions. Also, for what it's worth, Murdy in Hollywood has mentioned he definitely has an idea for the Phantom, so that could aid things in case both coasts want to do a shared property again.
Now regarding films with anniversaries and Slashers, well
@Brian G. beat me to the punch, here.
I know since it's an open season on spec, we can assume anything but do just want to point out that anniversaries don't necessarily mean anything. For example, Psycho celebrated 60 years in 2020 and was a staple of HHN's early years. No plans for it.
I'd also add that Chucky fits their "slasher" bill. Not saying they can't do another but...
Yeah, film anniversaries usually don't mean jack diddly in terms of being the reason why they're made into a house. Psycho's 60th didn't produce a house, and more recently the 40th for The Thing didn't give us a house this year.
As for a Slasher property for the year, Chucky honestly fits, and that house is 100% confirmed.
Finally, while I'm not 100% sure the film is being released in 2023...considering the fact the film will finally start shooting early next year, I do feel it's time we can add Five Night's at Freddy's to the spec list.
With Blumhouse producing that's one possible foot in the door, and if Uni ends up distributing it? That's the other foot! Now this will certainly depend on when the film is released, if it's released sometime in 2023, then I'd say it has a chance of being a 2023 house. As we know, A&D can be provided early scripts etc. to figure out what to do. Granted, what they're given might not even end up in the film, but enough about Dracula Untold. Now if it's not released in 2023, I'd say the property is a good potential lock for 2024.