51. Oniken - PC
52. Strife Veteran Edition - PC
53. The Mummy Demastered - Switch
54. Super Mario Odyssey - Switch
So I beat Bowser and did a bit of postgame stuff, but there is still a ton of moons to collect. Overall, I had a lot of fun with Super Mario Odyssey but I enjoyed Zelda more. I expect I'll plug away at slowly going for a 100% completion over time, as there are mechanisms in place to make it a reasonable goal (unlike the 900 Korok seeds).
So Odyssey involves Bowser kidnapping Peach to make her his bride (because he's a good devout evil lord who doesn't believe in sex before marriage), as usual. The twist is that your new power is your magic hat, with most of the bosses also having hat themed powers. The hat can be thrown out to collect coins, activate switches, and possess certain enemies. This is where a lot of the gameplay variety comes into play, as you will gain new powers as needed for short segments. So you might possess a bird to stick its beak into soft walls and then propel your way up, or a fireball to swim through lava. The hat also provides a bunch of mobility; when you throw it out you get a bit of an air boost, and you can jump onto a hat that has been thrown out for a boost. You can combine hat throws with other standard 3D Mario movement to create some really impressive movement chains, and this game is going to be amazing to watch speedrun.
The basic structure tends to be that you go to a world and get a couple of main quests in a series. This usually involves making your way to one or two bosses. Along the way you will have many opportunities to collect other power moons (the main collectable), and fortunately you just get a short ditty and continue. In order to move to the next world you need a certain number of moons from that specific world. I don't know if you can defer doing all the main quests or not and go to the next world, as I never tried; you can definitely get enough moons to qualify as enough without doing all of them. The other collectable is purple coins, which are unique to each world and can be spent in that world to purchase costumes and some souvenirs (which make your ship look nice). For the most part these costumes are meaningless, though certain moons are gated behind you wearing the right costume (which can be purchased in that world).
The game is fairly easy overall; in addition to the main areas you can go into pipes to get to specific platforming levels which can be harder, and there's also a feature where some pipes put you in 8-bit mode and you get to do a short 2D level in the style of the original SMB. These side levels tend to have a hidden moon in addition to the basic moon you get for completing the course, and these can be harder to get (though sometimes it's just noticing it's available). But all in all you should never be hurting to get enough moons for the next area, unlike SM64 if you got stuck on something. The levels will also transform a bit after a major quest, such as opening up new paths. This comes to a head when you beat the game; a very large number of moons (I'd say about 1/2-2/3) can't be collected until you've beaten the game, due to the necessary level changes not occurring until then. It ends up being a playbox; there's always something new to do every time you come back to it.
This is not my GOTY (that's probably Zelda), but it's still immensely fun, and definitely my favorite Mario game since World.