Played meta, thoughts:
Dynamax
The sooner we get rid of this mechanic, the better. Meta is very unforgiving against defensive play, thus limiting healthy growth, and even a fool would conclude this to be the main culprit. Z-moves and Mega's on the other hand are fine for now.
Ditto is a staple presence in BO, Balance and Stall, compressing checking prowess like no other in this offense-heavy metagame.
The defensive set falls short due to the abominable power creep at this moment, though it still works decently on Volt Turn. Scarf faces direct competition from Ditto. Its most potent set is definitely SD + Fly due to Dynamax, more so behind screens. I'd hesitate to still call it the king of the meta though.
Kartana is hands down the most potent Dynamax abuser with SD + Leaf Blade, Sacred Sword and Aerial Ace, leaving it solely checked by Ditto. The Scarf variant is also able to initiate its own sweep rather easily, while being slightly less prone to Ditto.
Shift Gear + Weakness Policy variants are extremely potent behind Screens. SG fares very well in general in this offensive meta, scaring plenty of frail Pokemon out in order to set up and clean from there.
Excadrill and Grimmsnarl are the faces of HO, being the reliable hazard and screens setter respectively. Both are upgrades from the past, with Excadrill free to run Toxic and Grimmsnarl being strictly better than Tapu Koko.
Heatran is quite a potent rocks setter, being able to set rocks against the majority of the metagame due to naturally beating defoggers such as Tornadus-Therian and Corviknight while luring the likes of Rotom-Wash and Tapu Fini with Max Overgrowth. Dynamax’ing in general allows it to trap a lot more threats than it used to with Magma Storm. It does provide Vish with free switch-ins though.
Both Ash-Gren and Gren remain potent forces due to their good matchup against offense, though Ash-Gren faces strict competition from Vish. However, it still has its merits in the current meta with access to strong priority.
Protean Gren is able to lure a good portion of the metagame with Life Orb boosted Max Move coverage, having access to STAB Max Quake, Max Overgrowth and Max Mindstorm. It is once again a great offensive hazard setter, due to its capability of beating every relevant defogger.
Toxapex feels worse than it was in SM/USM due to the fact that it gets overpowered by Max Moves and is unable to check Vish sufficiently. It isn’t bad by any means, but it doesn’t fulfil the roles you’d expect it to as the bulky water type in a team.
Aegislash finally feels like a healthy addition to the metagame (in any case, it is far from broken right now), which is exciting, as it allows unprecedented ways of teambuilding due to its unique set of resistances. It still does cause 50-50s, but in a less extreme fashion than it used to.
Dugtrio also doesn’t feel overbearing right now, but will most probably get better if Dynamax were to be banned. It still has a high viability ceiling though, since it has the potential to drastically alter the outcome of a game if one were to predict correctly. I haven’t tried Dugtrio Stall yet, so I can’t comment on whether that is good or not.
Dracovish is the most effective wallbreaker we have seen in a long time, being able to brutally 2OHKO even some of the sturdiest of resists. This will definitely be an influencing presence in the long term, mostly on the defensive metagame.
Darmanitan stands out as another strong addition to our pool of viable Pokemon. Band is less effective in NDOU due to its less than stellar speed, but Scarf has everything going for it and is able to frequently clean up in the late-game.
These two are nerfed more than the other Tapu’s due to the terrain nerf, because they don’t really have strong defensive niches they can fall back on, now that their offensive prowess is less effective. Moreover, Koko is strictly outclassed by Grimmsnarl as a Screens setter in non-Hawlucha HO.
I’ve found bulky Tapu Bulu with Def investment instead of Spd very effective lately, due to its ability to check Vish and Zygarde sufficiently while still serving as a good Ash-Gren and Koko check. Offensive Scarf and Band sets are still appealing too, especially since it can get rid of many of its checks through Dynamax.
This is the best mega by a landslide, acting as a glue for many teams while providing immense offensive pressure from the get go. I believe a set of Meteor Mash/Thunder Punch/Ice Punch/EQ is the best, but I’ve seen many variations, ranging from Rocks to Rock Polish.
Blastoise is by far the best mega on HO, due to its access to Shell Smash, a ginormous SpA and access to stellar coverage, for which it effectively gets a STAB boost. Nothing, except for Ditto, really checks it since traditional Water-checks such as Ferro and Pex are hit extremely hard by Aura Sphere and Dragon/Dark Pulse respectively.
I don’t know whether people have caught on, but this gets Stored Power now, meaning that it’s an exponentially more potent wincon and finally isn’t walled anymore by Unaware users if it opts for Double Dance.
Sun
Venusaur also got huge buffs in Weather Ball and Earth Power, which drastically boosts its offensive capabilities under Sun. Sun in general is probably worth it to experiment with this generation since we finally got a decent hazard remover in Boots Torkoal and many abusers are able to reset Sun with Dynamax.
Scrappy being immune to Intimidate is huge since this improves MLop’s mathup against Balance/BO quite a bit. It also means that it doesn’t have to dedicate Ice Punch for Lando-T, leaving a moveslot for the crucial Quick Attack in the current meta.
I really don’t understand the reasoning people are giving for a Kommonium Z + Clangorous Soul clause. Sure, they were never meant to be together, but the same can be said for NP Darkinium Z Hydreigon or Shell Smash Mega Blastoise. I don’t believe the community should resort to a complex clause here. If both together are overbearing, simply ban either Clangorous Soul or Kommonium Z, akin to UU in USM.
This shuts down so many rockers with Taunt + Pressure Defog, it’s seriously giving me Equilibra flashbacks. U-turn is extremely handy too, finally providing us a slow pivot with reliable recovery and good typing. Sub + BU is a very potent wincon too, especially if you were to Dynamax and collect Spe boosts.
Teams I've used to resounding success:
Vish BO
BuluTranVish basically provides you with the infamous Water-Fire-Grass core and the Dragon-Fairy-Steel core simultaneously, giving you a very solid backbone. Bulu is maximized in Def to properly check Vish and Zyg, while providing Grassy Terrain for Tran and MMeta. Ditto was added to improve the offense matchup and LO Torn-T is the defogger of choice, being able to take advantage of Dynamax, providing U-turn to bring Vish in and breaking bulky grasses for it. MMeta glues the team together by solidifying the Psychic/Fairy matchup and easily cleans up late game as soon as Vish is done.
Reuniclus Balance
This team basically revolves around Reuniclus. Dugtrio provides irreplaceable support by trapping Taunt Heatran and Dark-types with Reversal. Toxic is clutch in many situations, since it allows Reuniclus to outlast Dark-types it can't touch otherwise. Since Duggy is Focus Sash, I added Corviknight, since it's the most reliable defogger. Gastrodon was added to check water and electric types in one slot, while somewhat deterring Fishious Rend spam. It also complements Corviknight perfectly. Ditto improves the offense matchup and Greninja provides Toxic Spikes for Reuniclus, while beating all defoggers with Ice Beam/Max Overgrowth.
All in all, enjoying this meta the most of all. Would love to see Genesect/Landorus-I/Pheromosa/Deoxys-D unbanned and Dynamax banned.