I wouldn't call myself a particularly good player, but I've had some ladder success with this sand offense team:
Zacian-Crowned @ Rusted Sword
Ability: Intrepid Sword
EVs: 252 Atk / 4 SpD / 252 Spe
Jolly Nature
- Behemoth Blade
- Play Rough
- Crunch
- Sacred Sword
This is a fairly traditional set. My default is just to click Behemoth Blade, which hits opposing Zacian and Eternatus and the occasional Darmanitan -- it's quite spammable and even hits resists decently hard unless they're bulky. Play Rough is for random things weak to Fairy, such as Hero Zamazenta, but it seems optional until post-Home and I think you could slash it with Wild Charge for Corviknight. Sacred Sword is for Steel types; Zacian doesn't really want the defense drops from Close Combat IMO, and Sacred Sword hits Crowned Zamazenta and random mons that buff their defense (such as Excadrill after a Max Steelspike) harder. Crunch hits Aegislash, Corsola on the switch-in and Gothitelle slightly harder than Behemoth Blade, plus you can fish for haxy defense drops.
I'm not running Swords Dance because Ditto. It's just suicide, and I didn't find openings to use it. Zacian is well prepared for and in my opinion needs all the coverage it can get. I also think its speed tier is too important to run Adamant, particularly vs Band Zamazenta.
Zamazenta @ Choice Band
Ability: Dauntless Shield
EVs: 252 Atk / 4 SpD / 252 Spe
Adamant Nature
- Close Combat
- Crunch
- Psychic Fangs
- Facade
I like Facade because it's a nasty surprise for things which try to burn Zamazenta. I considered Wild Charge, but Zamazenta's other moves hit most of its other targets better and it's not a good move to be locked into. The rest of the moves are standard. This thing can usually take a hit from anything not named Zacian that has set up once, and Close Combat deals good damage to any switch-in not immune to it. I like Adamant because this thing rarely needs the speed and can usually take a hit from Eternatus, but I'll probably want to swap to Jolly when Home is released and Marshadow and Mewtwo enter the meta.
Eternatus @ Expert Belt
Ability: Pressure
EVs: 4 HP / 252 SpA / 252 Spe
Timid Nature
IVs: 0 Atk
- Dynamax Cannon
- Sludge Wave
- Flamethrower
- Recover
I've been unimpressed by Sludge Wave and will probably replace it with either Toxic or Sludge Bomb -- it's rare that I want the damage, and most of the time I used it, I was just hoping for a poison proc. Dynamax Cannon is for opposing Eternatus and general damage, as well as obviously chunking any Dynamaxed Pokemon that Eternatus can outspeed. Eternatus ends up hitting its target for supereffective damage more often than not, so I used Expert Belt for the 20% power boost, but I might experiment with Black Sludge and see if the loss of power makes much of a difference.
Ditto @ Choice Scarf
Ability: Imposter
EVs: 252 HP / 4 Atk / 252 Def
Impish Nature
IVs: 0 Atk
- Transform
This is Ditto. You know what Ditto does. Ditto is mandatory.
Excadrill @ Air Balloon
Ability: Sand Rush
EVs: 252 Atk / 4 SpD / 252 Spe
Jolly Nature
- Iron Head
- Earthquake
- Rock Slide
- Rapid Spin
This is a standard Excadrill moveset. Air Balloon was mostly for Imposter-proofing and better handling opposing Excadrill, but it has also been quite useful for getting around Sticky Web. Sadly, Excadrill is needed to offensively pressure the opposing team too often for Rapid Spin to be as useful as I'd like, but it's still a good option to have. Most commonly, I send this in under sand and proceed to Dynamax sweep. Needs to run Jolly to speed tie with itself, and to outspeed Jolly Zacian at +1.
Hippowdon @ Smooth Rock
Ability: Sand Stream
EVs: 252 HP / 4 Atk / 252 Def
Impish Nature
- Earthquake
- Roar
- Stealth Rock
- Slack Off
The extra 3 turns of sand from Smooth Rock is extremely useful for Excadrill, and Hippowdon walls a lot in this meta. Often I just sacrifice it to get Excadrill in safely under sand, but it's tanky enough that you can also sometimes put rocks up and just shuffle things with Roar. Helpless against flying types generally, but there's not much that can be done about that.
This team generally has a poor matchup vs stall (particularly Corsola, which dies to Eternatus but otherwise destroys this team), Corviknight, and opposing Hippowdon. In general, I think it could use a second special attacker of some sort, but ubers is pretty short on options.