Title says all.
Probably more Pikmin 4 and 1/2 Switch (ugh).
TOTK DLC (possibly)
No Pokemon (saved for Pokemon Presents)
No Metroid Prime 4.
Fire Emblem will get another (ugh) game, probably an Echoes game.
I honestly believe they'll have at least something about Super Mario there; could be a whole new main game or spinoff or just DLC for some already-made game. Another 2D Mario game? That's... also possible, if you think about it, but I won't get my hopes up.
Maybe a "GameCube games for Switch" announcement.
More ports (probably ports that I will be excited for, at the very least, as I don't mind them at all).
Xenoblade Chronicles X? Hopefully? I say it's 50/50 at this point. Who knows if they'll ever bring it back... (I hope so.)
More VNs (kinda goes back to what I said about ports but this especially will be there).
ActRaiser Renaissance 2? Well, that's more of a hope for mine.
A remake of an old NES/SNES game or series (in the same vein as ActRaiser)? Perhaps... Perhaps not...
Stray could make it to Switch for all we know.
No Switch 2. No sight of a Switch successor at all, in fact. Probaby not going to happen till 2024 at the earliest.
Tetris will be there in some capacity. Maybe a new Tetris game like the 99 one.
My guess is that this Direct will also be heavy on the ports and third-party games (but I could be wrong). Even if it is, there could be a lot of neat surprises, as has happened in the past.
No Super Smash Bros. It's not happening anymore. Probably not for another 5 years at the least and if we're lucky. And either way, I don't want another one for a long, long time. Super Smash Bros. Ultimate was the ultimate Smash game. No need to already go into yet another Super Smash Bros. game yet again.
"Unsafe" predictions:
The Legend of Zelda series will get another game, possibly made by Grezzo or another third-party or another team. Something like one of those remakes or 2D games or even OoT/MM-like games. I know it's "too early" but, honestly, I could see it happening as they always have a "second line" of Zelda games alongside their "main" Zelda games. In fact, they'll probably try to hype the Zelda series to get more people to get TOTK.
Another out-of-left-field remake or continuation of a long-dead series could also be a thing, like bringing back Baiten Kaitos, for example (same thing happened with ActRaiser, as I said earlier).
Star Fox might be there, though I wish it would stay dead at this point or they sit on it before doing anything.
I could also see another new IP being there by Nintendo; I think it's even a good bet.
But those are the only surprises I see happening; like I said, there will be surprises... but it will be heavy on the ports, third-party games, and, I guess, remakes.
Keep in mind that this is kinda their answer to "E3" month so that's something to consider.
And they always have a "But wait, there's more!" surprise at the end of their Direct (so it could possibly be a bit more than 40 minutes long).
Tl;dr for my predictions: heavy on the third-party/port/remakes (which I don't mind) but still some surprises (as usual) and that's about it; I'm not expecting much from this Direct despite its length.
One thing I hope they don't do is show another Splatoon game or Splatoon DLC or Splatoon, well, anything.
It will be forty minutes of execs taking turns making death threats to people who emulate games
They will announce some games will be released sometime over the next year