Hey all, I figured to stop by and give some thoughts on some winners of the Cinderace and Magearna quickbans, and explain some things I've toyed around with a bit!
Tapu Lele
Tapu Lele is a gigantic winner of these bans; namely, the Magearna ban. Magearna was one of Tapu Lele's better checks thanks to keen resistances to its dual STABs and a neutrality to Thunderbolt and Focus Blast. More prominently, though, Tapu Lele was setup/switch fodder for Magearna, which made it considerably more risky to use against Magearna teams. Without Magearna around, though, it is a lot more free to use a Choice Specs set, which makes me wonder if the use of SpDef Steel-types will grow over time, such as the aforementioned SpDef Corviknight and a resurgence of SpDef Heatran/AV Melmetal/Jirachi. Cinderace being banned is also pretty nice for it too, as now it is less pressed to run a Choice Scarf to revenge kill it; though, Choice Scarf will still be fairly solid given Tapu Lele's positive matchup against faster metagame threats like Dragapult and Hydreigon, and situationally Tornadus-T. Regardless of what happens, Tapu Lele was a major winner that I expect will considerably rise in usage.
Latios
A lot of people know I'm pretty enthusiastic about Latios's potential in this metagame, and the Magearna ban is absolutely monumental for it. Latios is now much less pressed to run Mystical Fire to cover the Magearna matchup and can more freely afford Aura Sphere, and now it is even more free to nuke with its STAB-boosted Draco Meteor and Psychic-type STAB. Likewise, I feel as though Future Sight has grown to become a more viable option for it as well, as now Magearna is not freely invited in whenever it wants to launch one. With Cinderace gone, its speed tier is even nicer, too, and it's no longer fodder to its U-turn. Though, I can see it competing with Tapu Lele as a Psychic-type wallbreaker; regardless, it still has some pretty great attributes we don't see with Tapu Lele, such as Draco Meteor, a better speed tier, longevity, better resistances, and Trick. I think Latios has always had potential, and it's without a doubt a Pokemon I expect to see as well now that its moveslots are more open regardless of the competition.
Kyurem
Alongside Tapu Lele, Kyurem is a major reason that I speculate that Jirachi is going to see an uptick in usage as both a special wall and cleric. Kyurem's stallbreaking competition in Cinderace has been banned, and one of Kyurem's better checks is gone now, too. Even with these Pokemon in the tier, though, Kyurem has seen a bit more use as of late with its terrifying Freeze-Dry + Earth Power + Draco Meteor, and I imagine it has the potential to become a legit wallbreaker again. Without Magearna, its Substitute + Roost + Toxic + Freeze-Dry set is a bit more freed up, too, but I don't imagine it will be as effective as its Choice Specs variant.
Rillaboom
This one has already been talked about a bit, and it's without question that Rillaboom definitely won, as the two slated Pokemon were ones willing to take on its Grassy Glides and threaten it out. Though, I don't feel as though these bans are necessarily a gamechanger for it regardless. Rillaboom still has the same targets, the same functions, and the same fundamental checks; although its Grassy Glides are a bit more reliable and easier to click, they aren't necessarily going to surge Rillaboom into a higher place in the metagame, though Rillaboom certainly isn't complaining whatsoever.
Blaziken
A major reason people avoided using Blaziken much, alongside its poop matchup against a majority of the metagame's premier physical walls, is because Cinderace was literally better than it in every way, shape, and form. Although it still faces the same issues it did prior to Cinderace's ban, I imagine people will start to use Blaziken as a way to try and compensate for the general lack of viable Fighting-types in the current metagame; though, I still don't think it's at all consistent outside of Screens HO. But, I think if there's a time for Blaziken to rise in effectiveness, it'll probably be now.
Jirachi
Jirachi, in my eyes, always had potential in the metagame, with solid resistances and neutralities and bevy of utility in U-turn, Wish, Healing Wish, and Stealth Rock. However, I think it was one of the big winners of these bans that will see steady use over time, as now without Magearna we will see Tapu Lele, Kyurem, and Latios as much greater threats, and Jirachi's neutrality to Fighting-type and Electric-type coverage lets it perform a fairly one-of-a-kind role as a special wall in the tier. I'm not sure if it will be a great Stealth Rock user since it doesn't really beat most forms of removal in the tier, but I think as a Wish cleric and a Choice Scarf user with access to great coverage and Healing Wish, it has quite a bit of potential.
Clefable
Clefable was complete Cinderace and Magearna fodder when it didn't click Knock Off, and to either the joy or frustration of many, that is no longer the case! While Knock Off was really annoying for these two for sure, I think we're likely to see a more variety in Clefable--namely with Calm Mind--now that it is more free to provide utility to teams and doesn't have to avoid giving either of these Pokemon an easy wallbreaking opportunity.
Corviknight
Corviknight has already been seeing a rise in use lately due to its amazing defensive typing and great removal abilities, and the Cinderace ban is gigantic for it, given that Cinderace was one of the primary ways of applying pressure to Corviknight teams. With this, Corviknight faces a lot less pressure and can afford to find more switch-in/removal opportunities; it also enjoys not having to soak Choice Specs Magearna's Trick/Volt Switch for the same reasons. It appears to be a solid check to Thunderbolt-less Tapu Lele and Latios variants, too, giving its defensive typing even more utility in the current metagame.
+ 
combo. Zeraora invites in Ground-types to get Knocked off, and Tangrowth just eats those Ground-types, meaning that the Ground-type potentially will switch out, and you can get another free Knock Off on something like a Flying-type, potentially removing HDB, making good progress on the game.
. It demands you to run things like fully specially defensive 
, if not, it will claim lifes everytime it has a free attack, however it has to predict correctly if the other team has more than one Ice/Dragon resist; for this reason the mon that i'm loving more and more is 
to check it, while also checking 
and 
. For 
, 
and even 
and SpDef 
to check 
to provide Defog support to not being overwhelmed by Spike stack while checking 
and 
; on the same vein, 
provides Defog support, it also checks the aforementioned Grass-types and checks 
, which Jirachi can invite in as Body Slam doesn't affect it. As Jirachi offers U-turn support, mons that can take advantage of it U-turning on its checks; things that can take advantage of Landorus-T, Heatran and Corviknight are good: comes to mind the same Kyurem, Aura Sphere Latios and Mixed Garchomp.
