TL;DR for those who don't wanna read a wall of text: fire type good. Make opponent sad. Make you happy if you use them so use them!
Hello everyone, today I wanted to talk about something that's been on my mind for a while, being the Fire-type and it's place in the OU metagame. Ever since I was a kid I found the Fire-type to be the coolest in the game, and after playing SS OU for several months now, I feel it is arguably one of, if not the best offensive types in the metagame. I'd like to use this post to explain my reasoning and maybe shed some light on some trends I've seen a bit lately. I'll break this into two parts: the type itself, and the relevant Fire-types in OU. First, the type itself.
It's no secret that the Fire-type is very strong offensively. It has only three resists outside of itself, being Rock, Dragon, and Water. Defensive Water-types are rampant in the tier, with all of Tapu Fini, the Slowtwins, Lord Pex, and even Swampert seeing significant usage. Needless to say, in one form or another, defensive Water-types are pretty much staples on most viable team structures. So what about the other two types? Let's start with Rock-types in OU. Tyranitar... and that's it. No other Rock-types reach OU usage. On top of that, Tyranitar is quite uncommon, especially in tournament play and the higher ladder. Unfortunately the removal of Pursuit hurt Tyranitar greatly. Not to say it's bad, but from this point on you'll start to see a trend with the rest of this post. So let's move on to the Dragons in OU. Dragonite, Garchomp, Hydreigon, and Dragapult are the four that made the cut. They all happen to be pseudo-legendaries too, so clearly they're quite strong by BST alone. However, if you take a closer look, you might see that pattern that I'm trying to show with this post. Of these mentioned, Dragapult is infamously an offensive demon, and while it has very useful resistances, it's defenses are lacking and often cannot switch in more than once on anything stronger than a resisted attack from a defensive Pokémon. Hydreigon stands out as a bulky pokemon with good resistances and typing, but it has an awkward place in the metagame at the moment and isn't the most used pokemon out there. Dragonite also falls into this category too. Good bulk and defensive typing, but its days of being a defensive Pokémon are basically behind it once people realized that it's a complete momentum sink. It's still a threat offensively with its DD set that shouldn't be slept on, but it's still uncommon on most team structures. Finally we get to Garchomp. Not counting Dragapult, Garchomp is clearly the best of these, and also the most versatile. Do you want a sweeper that can clean weakened teams with ease? SD Scale Shot. Do you want a Stealth Rock setter that makes physical attackers sad with contact moves? PhysDef Rocky Helmet. Hell, I've even played around with a specially defensive spread with Protect to keep heatran in line and disrupt special attackers with some success. Garchomp is a mon that has stood the test of time generation after generation and has found a way to be a staple in the metagame every time.
All that being said, lets circle back to the Fire-type. Quickly I wanna mention that being super effective against grass and bug types is cool but the most important type is steel, given how you'll find at least one on every team, and it's the only type that's 4x SE against both Scizor and Ferrothorn, 2 mons notorious for their longevity.
Back to the resistances, there's a pretty clear trend I noticed (sidenote: I'm omitting Fire-types here because I'll get to all the mons below in pt 2), outside of bulky Water-types and Garchomp, and Heatran with Flash Fire, there aren't a lot of mons that reliably resist Fire-type attacks. Some more uncommon mons like the dragons I mentioned and TTar come to mind, but finding a resist for a Heatran Magma Storm or Blacephalon Overheat that isn't a Water-type is pretty hard. They exist, sure, but those that play regularly know how hard these mons are to switch into due to common answers getting worn down and the coverage moves these mons regularly carry.
And therein lies the point I'm trying to make. Finding reliable switch-ins to these mons can be difficult. Toxapex doesn't fit on every team structure and has to be wary of Future Sight support. Tapu Fini is great, but it's downfall is the lack of reliable recovery it has outside of Leftovers and it is often prone to being worn down over time. The slowtwins are great (yes, including Slowking. Fite me), but aren't the most used and dislike the prevalence of all the Ghost and Dark moves being thrown around. Swampert is kinda meh, and the least seen in higher level play. Funny enough, Dragonite and Hydreigon are two of the more durable resists out there, but as I stated above, they're not terribly common and can sometimes have trouble finding a teamslot. I don't want to downplay their usefulness, as all these mons are very good and integral to many team structures, but we're starting to see the limits of reliable fire resists.
Edit: noticed I forgot Gastrodon. It's a good defensive mon but really only fits on fat teams and can be a momentum sink. Suffers from low usage as well.
So what about non resists? You have mons like blissey, the catch all for special attackers, but even she can get overwhelmed through U-Turns and double switches and often has to choose between teleporting or healing itself. Hippo is a durable ground type with reliable recovery and scares these mons out with SE EQs, but it's not much of a threat to anything that can eat its Earthquakes and doesn't fit on every team. Even OU Overlord Lando T has problems with being a catch all, as it can be overwhelmed and is prone to being worn down over time. Tornadus-T can take a hit usually but often cannot repeatedly switch in, and it's forced out to regenerate its health after it knocks an item usually. Good mon, but it's not repeatedly eating magma storms or overheats. Urshifu can take physical hits well, but it's poor special bulk means it has one or two switchins at best, and doesn't like the common coverage moves seen on mons like blacephalon and volcarona. It's excellent offensively though and if it gets in safely it almost always forces them out. Finally we reach Galarian Slowking, the pinnacle of BO special pivots. It's great, and one of the best mons in the tier, but it can't reliably handle any fire type. The special attackers like heatran and Blacephalon just punch past it, and it's not known for its physical bulk. If it carries EQ it can beat Heatran if healthy, but aside from this specific interaction it's a suboptimal moveslot.
So to conclude this long wall of text, the Fire-type is excellent offensively. While having a common resist in water, coverage moves and teammates can pressure them greatly (anyone notice how well Fire-types synergize on hail? Look at the best Hail teams. You'll see one). Furthermore metagame staples that can take hits have drawbacks such as passiveness and proness to being worn down. The lack of common resists outside of the water type goes heavily in the favor of Fire-types and as such are seeing a lot of success currently.
I don't want to do a deep dive into Fire-types defensively, as I'm focused on their offensive prowess in this post, but I would like to quickly mention that they have a very useful resist to fire(!!!) and Ice, Heatran is one of the best mons in the tier, and Boots mean that Stealth Rock isn't as much of a worry for things like Victini or Volcanion like it used to be in years past. Not the best defensive typing out there, but not the worst. I'd say solidly average with some really nice upsides.
So now I'd like to dive a bit into the Fire-types that see usage in OU. This list isn't in a particular order, but I'll try to keep the ones that are OU by usage at the top.
The metagame defining threat that makes players tremble in fear on team preview, we'll start with the S- threat in Heatran. It's no secret that Heatran is one of the most oppressive threats in the tier. It's staple spdef Stealth Rock set is not only one of the most consistent defensive mons in the tier, but it is also offensively threatening as well. Magma Storm is notorious for being difficult to switch into repeatedly, which is often relegated to fat waters and grounds. However, even these have to be careful of being overwhelmed, as it's not uncommon for heatran to power through them. Assuming all its moves hit, of course. Capable of fitting on basically any team structure, it's only true downside is its lack of recovery outside of Leftovers. Even then, it has surprising longevity if it doesn't get knocked off given the amount of switches it forces. It's even seen wearing some fashionable specs every once and a while and nuking shit with Eruption. Probably the best showcase of this was when
Ox the Fox used it in WCoP finals to great success and it claimed over half the opponents team. And it wasn't even on a sun team! Another thing I'd like to note I that I believe Heatran is one of the best Future Sight abusers in the tier. Hydreigon, Slowking, and Tyranitar are the only mons capable of stomaching this combination repeatedly, as typical switch ins like Pex and Garchomp get nuked by the impending Future Sight. FS is notorious with Urshifu, but I think Heatran is slept on as an abuser and I wouldn't be surprised to see the combo popping up more and more.
The infamous matchup moth is back in OU once again, all thanks to its shiny new boots. Cries for a ban rang across the tier a few months ago, as it terrorized teams (and my dreams) far and wide. It only really has one true counter in heatran, as everything else can be accommodated in its moveslots. Unfortunately hidden power got nuked, but that hasn't stopped Volcarona from finding its place in the meta. The metagame adapted to it, and it's usage fell quite a bit recently, but some recent SCL games showed some new techs that proves its capable of adapting to what OU throws at it. It's always a threat, and lives up to its moniker. If one isn't careful, it's just one Quiver Dance away from sweeping your team. Sidenote: it's probably the only true Kyurem counter in the game with its bulky QD set.
That's it for Fire-types OU by usage, but there are still several more seen in the tier.
The Blaze Chicken was finally freed from Ubers after a long decade in the abyss. Cinderace took its place as the Fire-type starter to be banished, and Blaziken has done its best in OU. It's obviously the coolest mon ever and an S++ mon and everyone should use it. Moving on.
I kid, but I do feel Blaziken is slept on right now. It probably won't 6-0 a team turn 1 like it could in the past (though I have done that before), but it got some cool new toys in SS like Close Combat, U-turn, and Knock Off(I think it was gen 8?). Close Combat forgoes 10 BP in favor of 100% accuracy and not losing half it's health on missing HJK. Both Choice Band and Swords Dance are viable, though the latter is more consistent in my opinion. Landorus-T moving to SpDef, the relatively low usage of Slowbro, and offense being the predominant playstyle all work in favor of Blaziken. It's not the most consistent mon, but if it gets a free turn it can often claim a kill or two. Fire/Fighting STAB is incredible, and Speed Boost on top of it makes revenge killing difficult outside of priority. All that being said, Blaziken often kills itself with LO + FB recoil on top of Rough Skin/Rocky Helmet shenanigans, so it's staying power is limited. Furthermore, it needs a Jolly Nature to outspeed metagame staples such as Dragapult and Koko at +1, which hurts its damage output. It can also struggle at times with some current fat cores and doesn't always have an opportunity to set up. It's no longer the Uber worthy threat it was in years past, but I do think it's a mon worth exploring in the current metagame. I've had a lot of fun with it recently and I think others will too (RMT coming soon)
The faceless clown has seen a spike in usage thanks to people realizing that Fire/Ghost coverage is resisted by only TTar and Hydreigon, and form an very potent STAB combo. While blace has piss poor defenses and is Stealth Rock weak, it nukes something any time it gets a free turn with its specs set. Furthermore, beast boost means it's capable of snowballing out of control quickly. It has a very good offensive matchup vs offense as they often lack a switch in, so positioning sacks becomes paramount facing it. Furthermore, scarf is a pretty good late game cleaner thanks to it not fearing many priority moves and an excellent speed tier. It's not the best mon out there because it doesn't really switch in on anything and dies to a sneeze, but it's still a threat nonetheless.
Probably the most versatile on this list, it's very much a jack of all trades, master of none type of mon. It can nuke shit with Banded V-Creates, or be a potent pivot wearing its favorite boots and U-Turn. It's often seen as a physical attacker, but recently Glaciate has caught on to lure in Garchomp, Landorus-T, and Dragonite. I've also seen people experiment with special sets that make use of expanding force paired with Lele, and even some FS shenanigans since it forces a decent amount of switchins. Victini does suffer a bit from disappointing power output aside from V Create and SE coverage, and its defensive typing, while useful, leaves it prone to being forced out by some metagame staples. A reliance on Boots means it has no recovery and cannot afford to get knocked off at all. Despite these flaws, however, I wouldn't be surprised to see it reach OU usage soon given its positive traits.
A very recent development in OU, Volcanion sees a majority of its usage on weather based teams. It's a nuke under rain with specs and it synergizes very well with Hail, which is evident in the infamous Ox Hail team (I'm starting to see a trend here
). I've also seen it pop up on general offense and balance teams. Both boots and specs are useful and I've seen both used to great effect. On top of that, Fire/Water is a sneaky good defensive typing and 80/120/90 bulk is nothing to scoff at. It's a very recent metagame development and I'm not sure if it's a passing fad or here to stay, but I'm interested in seeing its usage develop over SCL.
I'm lumping these two together since they're only ever seen on Sun teams, but Torkoal is the only good sun setter and has excellent utility with rocks, rapid spin, and shit like yawn and lava plume to not be completely passive. On top of that its physical bulk is really good and it can even be EVed to hit hard, as seen in some Sun RMTs that are floating around. Unfortunately, rest is its only recovery and its weak to rocks so it doesn't have the most longevity, but it's often able to set up the sun at least twice a match and enable some powerful mons.
Darmanitan is simple: Fire Gorilla go ham with Banded Flare Blitz in sun. Even resists are crying after taking sun boosted attacks from this demon. It sucks outside of sun teams and has no longevity at all, but it nukes things with its attacks and can be scary to face. Remember how I said fire resists aren't terribly common outside of fat waters above? This mon makes fat waters look like grass types with the damage it does. It's a fun mon to try on sun and seeing the damage output is insane.
Pls don't use this mon it sucks.
I might be missing some niche mons but I think I've covered all the common ones.
All of the mons I mentioned are good, and some are incredible. I wanted to bring everything together and conclude this wall of text by saying that I think the common denominator for all these mons is a lack of consistent resists for their main STABs and coverage aside from a few select pokemon, which I touched on in the post. Hopefully my post was coherent and I was able to explain why I think the Fire type might be the best offensive type in the game. I realize that Ghost, Fighting, and Ground are all incredible and have cases for the best offensive types (along with Dark they're certainly in the top 5) in my opinion. I glossed over its super effective coverage pretty quickly, but SE coverage of Grass and Steel in one typing is incredible and something that should not be taken lightly. I'd elaborate further, but I think this post is long enough. To conclude, for the reasons I explained I believe that the combined traits of several prominent STAB users, lack of resistances, great neutral coverage among STAB users, good SE coverage, and the fact that many mons carry Fire-type coverage in their own arsenals make for the best offensive typing in the tier.
If you made it this far, thanks for reading :)
. If you don't like those, go buy a burger or something
Previously considered heavily outclassed without Cinderace in the tier, Hippowdon managed to make a resurgence with specially defensive sets, which let it check Dragapult, Volcarona and Heatran, and most importantly deal with the various Electric-types better. Unfortunately, its passivity restricts it only to bulkier balance and stall teams, and it usually finds itself the most easily pressurable Pokemon on the planet, making it often check Electric-types a bit less well than it first seems it should. 
It doesn't feel like long ago that Excadrill was A-rank, back in the Magearna meta. Now it lies forgotten, ready to drop to UU in a few days time (I can imagine some older gen players crying right now if they were able to see that we managed to kill all of Skarmory, Tyranitar and Excadrill's streaks in OU in the same generation...) While clearly Excadrill is long beyond its prime days, I think some people underrate it a bit: it's a good Arctozolt check and the only Ground-type that checks Tapu Koko long-term. We'll have to see if it manages to make a comeback at some point..
Gastrodon is used on bulkier teams mainly for its ability to be the best Heatran check in the tier, and it is also the only Pokemon that can check Choice Specs Volcanion in rain. Unfortunately, it is often difficult to justify on teams due to its extreme passivity and lack of momentum, and Light Screen Toxapex is often preferred as a Heatran-checking Water-type on balance teams.
Once the initial hype of a starter getting a cool new move died off, we realised that Flip Turn didn't really do that much for Swampert, it still is a Stealth Rock setter that has a good typing to check a lot of things but terrible longevity. It can still work fairly well on certain teams as a pivot and rocker, usually structures such as Grassy Terrain teams.
I tried Mamoswine a bit a while ago and wasn't sold on it - it's walled by Corviknight (not usually a good start), provides near zero utility and doesn't have a lot to stand out offensively. Maybe I'm using it wrong though, if anyone more experienced with it thinks they can make it work then good luck.
Quagsire is an alternative to Unaware Clefable on stall teams, providing more physical bulk to better check Pokemon like Melmetal and Tyranitar and the ability to be a secondary Heatran check. Its viability ends up constrained mainly because of stall's limited viability in general.
While defensive Seismitoad from the days of Dracovish has not lasted, it is a solid option on rain teams, providing Stealth Rock so you don't need it on Ferrothorn as well as an extremely useful Electric immunity. There have been some different things seen on it, like Focus Punch to lure in Ferrothorn and Blissey.
