I'm looking at it now
You can use them to have early- to mid-game pressure, as they excel at wall-breaking and punching holes at your opponents team.
I'm not sure about the - after early, but that could be right and I'm just an idiot.
There are some contractions about, we don't require removing them but in some cases it is better - your judgement
due to their type weaknesses that are common in OU (Rock, Water, and Ground)
I'd remove the word "type" it is implied.
Pokémon who know Defog and Rapid Spin like Latias or Excadrill are good teammates to have with them, because they remove Stealth Rock, making it easier for Fire-type Pokémon to be switched in, if they need to.
Run-on. I'd just remove "if they need to" and call it a day, as they obviously will only be switched in if they need to be in.
Extra space after Suicune
Suicune can threaten Ground-type Pokémon which are problematic for the Fire-typed Heatran, a while Heatran in the same party, deals with Grass-type Pokémon, which Suicune, a Water Pokémon, has difficulty against.
A number of unnecessary commas and messy word placement. I'd rewrite this "Suicune can threaten Ground-type Pokémon, which are problematic for the Fire-typed Heatran, while a Heatran in the same party deals with the Grass-type Pokémon that Suicune, a Water Pokémon, has difficulty against."
looking at it's offensive set
its (possessive) > it's (it is)
is good for added pressure, and for stall breaking
Remove the comma, list of two items don't deserve them.
At some points (i.e. the first Heatran set) moves are bolded, whereas others (i.e the second Heatran set) they arent. Choose one and stick with it. Heck, the MZard X set has DD bolded but nothing else
Mega-Charizard X specializes in it's physical sweeper set:
its > it's
see above
Flare Blitz and Dragon Claw are it's primary STAB moves, with Roost being its recovery move
You have managed to use its twice in a sentence and messed it up only once. That's something I would do. That means you shouldn't do it.
It has an interesting typing, with it being part Dragon-type, so you can even use it to set up on bulky Water-type Pokémon, but it's mostly recommended to set up Dragon Dance on Pokémon that it forces out like Scizor or Mega-Manectric.
Split into two sentences.
Due to it's Drought ability, it can use the sun to power up it's Fire-type moves
Solar Beam is there with the sun thanks to Drought, to hit Water-type Pokémon, and Focus Blast to hit Tyranitar, or Heatran for super-effective damage.
"Solar Beam can hit Water-type Pokémon in only a single turn due to Drought, while Focus Blast hits Heatran, Chansey, and Tyranitar."
Air Slash is also an option, but, but as effective to use coverage use.
"Air Slash is also a viable option for a secondary STAB with a flinch chance to boot, but everything that it hits super-effectively (except the rare Fighting-type) is also weak to Fire."
Volcanion is really powerful, and it's pretty bulky. It's Water Absorb ability allows it to even come in against strong Water Pokémon like Azumarill and be an effective check. It's most notable set is it's Choice Specs set:
Three of those it's need to be changed to its, but the first one can stay as-is.
Steam Eruption is a scary move; it works the same way as Scald with it's added 30% of a burn, but more powerful.
I'd replace that semicolon with a period, and add "it is" before "more powerful". Also its.
Don't be afraid to use that move often if you see that your opponent has Pokémon that has Water Absorb, as the added burn effect is very nice for pressure.
Water Absorb also negates the burn chance.
The accepted community term is "revenge-killer"
thanks to it's Gale Force ability, allowing it to gain priority for its
First one needs to be changed, second its is fine.
People also tend to use it as a defensive Pokémon as it can use moves like Will-O-Wisp and Bulk Up respectively.
Comma after Pokémon. Respectively isn't the right word here, as it implies two subjects. Try "respectably".
Roost's effect on removing it's Flying-typing after it's been used.
of > on. The sentence implies Roost as the subject, so the first it's needs to be changed to Talonflame's. The second its needs to be "it has" for grammar reasons that I can't remember rn.
use Taunt to prevent Pokémon on using Toxic or Whirlwind
Extra space after prevent, from > on
You wouldn't want an item since Acrobatics gains power if Talonflame is not holding an item, but, you can also use Leftovers
remove the comma after but, explain why you would even consider running Leftovers (more recovery), offer another option should you choose to run Lefties (Brave Bird), and end the sentence with a full stop.
Another set is it's more offensive set:
This time having Swords Dance, Brave Bird, and Flare Blitz.
This sentence has no subject. Add one (hint: add a comma after time and change "having" to "Talonflame has")
The remainder of that paragraph is one giant run-on sentence. Split it up into 3 or more.
and it's other versatile moves for it's set like
Or, it can have a Life Orb alongside moves like Glaciate and Energy Ball.
Replace Or with "Alternatively" or something to that effect. Starting a sentence with a conjunction is allowed, but doesn't work well here.
Mention that Ninetales also doesn't use your Mega slot, which MZard-Y does.
If you like having your teams have a more offensive approach
extra space after have. Also, using having and have so closely to each other sounds weird. Replace the latter with use, or remove the first and put the word "to" before the second.
These are the things I noticed, do what you will with them.
