So what are everyone's most unexpectedly good sets? "Unexpectedly" varies from person to person obviously, but there's a number of sets I took one look at and knew they were good. Some others, on the other hand...

Flower Gift
Solar Beam/Worry Seed/Sunny Day/Weather Ball
I mentioned Cherrim a week ago, and guess what: it still owns. It provides such an easy boost to your whole team with Flower Gift (50% Attack and Special Defense), and even after setting up Sunny Day it's a respectable attacker in its own right with Solar Beam and Weather Ball. I picked it the first time cause I thought it was a cute gimmick, but it's actually so good. I two-turned a Dialga with this, Hitmonlee, and Rhydon, lol. Even the AI seems to know to just pick Sunny Day turn 1. The only flaw is that it is incredibly reliant on weather, so Pokemon that can overwrite it are kind of problematic. But only kind of, it's not like they overwrite the weather every turn, and even just 1 turn of Flower Gift is often worth the Sunny Day turn with the right team.

Aftermath
Lash Out/Burning Jealousy/Acid Spray/Sucker Punch
Acid Spray is so nice, and this is in a fun speed tier where it can both Acid Spray before others attack, but also slow enough to do fun Lash Out combos.

Adaptability
Liquidation/Dive/Psychic Fangs/Ice Fang
This hits quite hard, and if you can dynamax you get a rain boost to really go off. Dive is really clutch when you're low on health too; you can still deal decent damage while avoiding some attacks. The coverage looks nice but if you feel obligated to use it you're missing the point of Basculin. Also the blue stripe one is respectable too with Scald, but this one is just better to me.

Static
Electric Terrain/Thunderbolt/Earth Power/Muddy Water
Stunfisk is one of those Pokemon that always has better stats than I assume, and this mode is no exception. It has really good moves and takes most hits.

Battery
String Shot/Eerie Impulse/Spark/Dig
Like Flower Gift, Battery is really good in raids. String Shot and Eerie Impulse are great support on top of that, and Dig is fun for avoiding damage after debuffing, since it's not like this is dealing that much of it anyways.

Queenly Majesty
Aromatherapy/Trop Kick/Acrobatics/Swagger
This has good enough bulk to take a hit, and Trop Kick does consistently good, if not great, damage while neutering attack. I tend to like Skitter Smack for the same reason, but this is a cute (this was a typo but I'm keeping it tbh) above since this is quite a bit stronger than those. Acrobatics is coverage I guess, but ideally I just want to Trop Kick. Aromatherapy is also nice to heal status on the way to the boss.

Sturdy
Nuzzle/Poison Jab/Electroweb/Iron Head
Speed control is often nice, and with the new mid-turn speed change mechanics it's especially nice on a fast Pokemon like Togedemaru. It's often bulkier than expected due to Steel's million resistances, and even for stuff like Kyogre it has Sturdy to come in clutch. Iron Head then deals decent enough damage after speed control.

Cheek Pouch
Gyro Ball/Psychic Fangs/Body Slam/Swords Dance
Decent for the normal fights, but in the longer boss fights Swords Dance really shines, especially with Greedent being hard to OHKO. The 30% paralysis chance is delectable as always, too.

Serene Grace
Skitter Smack/Dual Wingbeat/Shadow Ball/Ice Beam
Okay, maybe this doesn't belong on a list of unexpectedly
good Pokemon, but damn if this isn't a lot better than it looks. I've had the uh, fortune...? to have seen this multiple times when nothing looks good, and it always ends up being a respectable choice. Skitter Smack has great utility, and this hits a lot of things super-effectively in general. Serene Grace can be nice with Shadow Ball too, and outright amazing with Ice Beam.