I gave Medicham the Muscle Band so it isn't totally worn down by Life Orb recoil on top of potential Rocky Helmet chip from walls like Sandaconda and Palossand, especially because the focus is on Medicham using Fake Out. I chose Bullet Punch so that Medicham isn't a total sitting duck in the face of Whimsicott, but it could easily be changed to Ice Punch or a different coverage move.
I chose Muk instead of Weezing because it can remove Heavy-Duty Boots with Knock Off and take on Whimsicott for Medicham. The Toxic Spikes should help wear down Spiritomb, which would otherwise wall this Medicham set. The Toxic Spikes can also be nice against walls like Dipplin and HDB-less Palossand, especially since this Medicham doesn't run Ice Punch.
Sandslash is the hazard remover for the team since Hitmons would overlap Fighting typings with Medicham and Hisuian Avalugg didn't seem like a great addition. It should also help against the grounded Poison-types like Hisuian Sneasel and Hisuian Qwilfish somewhat so they have a more difficult time removing the T-Spikes.
Mismagius is here to give some more Speed to the team and do some spinblocking while it's at it. Substitute can exacerbate the damage from poison, and Mismagius can clean more effectively with the chip damage from T-Spikes.
Double pivot move Lanturn makes sure you're going to switch out and bring Medicham in slowly, no matter what. You could flip one of Lanturn's other moves to a status spreading move if you want, as Medicham's Fake Out can milk burns and Medicham itself enjoys running over paralyzed foes, but the goal of it is mostly to be a turn bot that can check Fires and sort of Floatzel.
Whimsicott is additional speed control and answers Dipplin, Sableye, and Spiritomb. Whimsicott can also lure in special walls like Porygon2 and Articuno for Medicham to take advantage of.
Support Medi
and/or 
. As you probably already know, both of those have fallen off from the generations you are clearly fond of, so a team with both seemed out of the question. However I've got two teams using both to their "fullest".
Morpeko was a threatening and fun choice as a Choice Band user, as STAB Aura Wheel made it difficult to stop without faster Choice Scarf users like Floatzel or the niche Scarf Typhlosion at +1, and outsped even all Choice Scarfers at +2. A Tera Dark Aura Wheel is notable for Knock Off added more utility and consistent Dark-type damage early-game. I ran with Seed Bomb to hit Rhydon, though you could also go with Psychic Fangs for Decidueye-Hisui and Virizion. Parting Shot made it a solid pivot and made Mesprit and Porygon2 better at tanking hits. Be aware of the type you terastalize into, because Morpeko will stick to this type of Aura Wheel (i.e. Hangry = Dark, Full Belly = Electric).
I went with standard Boots Sneasel due to a lot of my team lacking Boots or being vulnerable to hazards in other ways. Sneasel was my priority user and cleaner, helping pick off many Ice-weak threats like the aforementioned Grass-types. Sneasel gets the leg up on faster weakened threats like Charizard and non-Scarf Grafaiai while also finishing off powerful attackers like Whimsicott and Jolteon.
With Eviolite, Porygon2 is the bulkiest special wall (and a great general wall) and boasts additional utility with Thunder Wave and Trace to net additional great matchups. With special monsters like Jolteon, Charizard, and Magneton running rampant, the devilish duck provides a much needed defensive backbone. That being said, this team looks awfully Fighting-weak. Which leads to my next pick...
Mesprit was a mandatory pick here, once again providing valuable compression. A Ground immunity, Stealth Rock, U-turn, and some nice bulky setup deterrent with Psychic Noise. With how well Morpeko exploits Thunder Wave, a second user didn't hurt. Mesprit also provides decent physical bulk when invested, though it shouldn't be the team's designated wall with its lack of recovery.
The team's speed control. Scarf Qwilfish has been consistently solid yet underrated. A lot of peeps gear towards bulky physical wall sets for Spikes/status spreading, but Mesprit alone was vulnerable to being overwhelmed by Fighting-types, especially with Passimian in the picture. Qwilfish provided much needed backup for Scarf Passimian and a water resistance for Floatzel, while also being a good Toxic absorber. Destiny Bond was thrown for the last slot to surprise unsuspecting Dipplins or offensive Mesprits looking for easy pickings. Flip Turn was provided for more pivoting.
The best Defogger in the tier and because you can never have enough pivotters. The best hazard remover in the tier and Triple Arrows is a broken move. Provided a secondary Ground immunity and was a physical wall with reliable recovery.
first off that set is really fun to sweep with when it gets going. the second mon to help 
at this point the fire weakness stand out like a sore thumb so well baked body 
provieds a fire immunity and wish support also to keep the team healthy while checking the fire types in the tier. 
- Very slightly different to the set you 
- Poliwrath synergises well with Magcargo, allowing it to take Water-type the team would like to absorb. Poliwrath functions as a setup sweeper with Bulk Up and Substitute. Knock Off helps provide utility, removing Heavy-Duty Boots from the opponent's team.
- Strong physical wall that compliments Magcargo through its ability Levitate nullifying Ground-type attacks. Haze helps to stop any form of setup sweeping from happening. Tera Steel turns its weakness to Psychic to a resistance.
