When it comes to Pokémon, there are a few different ways to judge relative strength.
Canonically, it's hard to argue against Arceus being the most powerful Pokémon, being a literal god who created the entire universe. Then there's Mew, who is basically the predecessor to all Pokémon in existence.
On top of that, we know each generation has legendaries that are basically built to wreck shop on everything else in sight.
But for you pros out there, the ones who actually put in the work to be the very best, like no one ever was, none of those are viable options. Even if you're willing to go through soft resets for hours to get the nature and IV values you want on those legendaries, you still can't use them in tournament play (at least most of the time).
That's fine, though, right? It's way more satisfying to score a victory with smart tactics and good strategy than with sheer overpowering force.
...well, just in case, here are some Pokémon to consider that will give you both.
And by the way, we're not covering Mega Evolutions or Z-moves here, because in most places those are either banned or probably about to be.
Oh look, the ninja frog is strong. Shocker.
Greninja has its share of problems, not the least of which is it's weak defensively and has relatively vulnerable typing. Of course, if you're using Greninja correctly, you might never even get hit.
Greninja is a fan-favorite sweeper who has two very important things going for him. The first is one of the highest base speed stats in the game. The second is Protean.
Protean is a hidden ability that changes Greninja to the same type as whatever move it uses. That means two things. First, every single attack you use gets STAB (Same-Type Attack Bonus). That's just a 1.5x damage multiplier on every single move you teach it.
Second is that you can also use Protean defensively. Electric type looking to ruin your day? Use Grass Knot, become a grass type, and cut that Thunder damage to a quarter of what it would have been.
Greninja can learn moves (either naturally or through TMs) that are Water, Dark, Ice, Psychic, Fighting, Normal, Ghost, Ground, Rock, Flying, Grass, and Bug. That means it can be any four of those types on demand in a single battle, with offensive and defensive bonuses to match.
First off, let's all take a moment to appreciate the fact that a bird luchador with Flying/Fighting typing is absolutely radical. Someone actually thought of this and designed it. Think about that for a second, and then take another second to be sad it wasn't you.
Okay, so design love aside, Hawlucha is another good speed/attack Pokémon who isn't going to do much tanking. But what makes Hawlucha really interesting is a particular combination of moves, especially if you have the right held item.
Here's what you do. Get a Hawlucha with the ability Unburden. Unburden, if you're unfamiliar, doubles a Pokémon's speed when they use their held item. By the way, that does mean "doubles." Not "increases." Doubles. That is to say, you're now faster than everyone forever.
Now, you're going to want to make sure that Hawlucha knows Sky Attack and is holding a Power Herb. And if you know what those things are, you're starting to see how this comes together.
Hawlucha uses Sky Attack, a devastating two-turn Flying-type move with a power of 140 (plus STAB, so it's actually 210) and a 30% chance to cause a flinch. The Power Herb, a held item that allows a two-turn move to be used immediately, is consumed and sends Sky Attack out instantly.
Using the Power Herb activates the Unburden ability, doubling Hawlucha's Speed stat. If you can manage to get a Swords Dance in somewhere along with all this, you're basically an unstoppable monster going Flying Press all over the place for the rest of the match.
Aegislash - the whole Honedge evolutionary line, really - also makes a lot of "dumbest Pokémon design" lists. But who cares about that? This thing has King's Shield.
Okay, Aegislash is kinda complex. It has two modes: Sword Mode and Shield Mode. Just like they sound, they're basically offensive and defensive stances. Shield Mode is the default mode, which allows you to tank hits with high defense. The moment you launch an attack, it switches to Sword mode, taking that excess defense off and adding it to offense.
Okay, but how do you switch back to Shield Mode? With King's Shield. This Steel-type move is a variant of Protect, which negates all incoming damage on the coming turn. It always goes first, and if the attacker makes contact with the shield, its attack is lowered by two stages.
So basically it's a defensive move that has the ability to completely cripple your opponent's attack. On top of that, you get natural type resistances to Grass, Flying, Rock, Steel, Psychic, Ice, Fairy and Dragon-type moves, double resistance to Bug moves, and complete immunity to Normal, Poison and Fighting.
You just can't deny that face that says "DURR, ME DRAGON NOW!"
Seriously, though, while Alolan Exeggutor is best known as a meme, it has some tricky strats you can pull off with it. First off, its new Dragon typing makes it easier to stand up to Fire and Dark attacks that rocked it before. The tradeoff is a 4x weakness to Ice attacks, so look out for that.
But what makes Alolan Exeggutor interesting is its stats. It has rather high base stats except for one: speed. Normally that would be a death blow in competitive play, but it has an ace up its sleeve: Trick Room.
Trick Room flips things around to make slower Pokémon go first for five turns. Since Exeggutor is super slow, that means he'll probably get the initiative for the rest of the fight. And since most Pokémon trainers focus on high-speed teams to get that initiative, this can be absolutely devastating if you stack a couple of low-speed bruisers on your team to take advantage of the new environment.
First off, Bug/Fighting is a cool combination, just in general. But it also covers a lot of weaknesses. Fighting helps take out Steel and Rock types that would normally wall Bug types, and the Bug typing covers Fighting's weakness to Psychic.
That said, you don't want to be taking a ton of hits as Pheromosa, with its super squishy low defense and HP stats. You'll want to use it as a sweeper, as it has very high speed and attack stats.
Pheromosa also has something really interesting going for it: U-Turn. U-turn gives Pheromosa the rare ability to pull off some fun hit-and-run tactics, which helps cover its squishy nature.
As it is, U-Turn is a fairly strong (70 power) Bug attack that will give you STAB damage. But the move also switches Pheromosa out instantly after the move, negating any counterattack chance.
This makes Pheromosa a great option to send out first, as you can get in some good damage (assuming it's fast enough to go first, which it usually is) and then switch out to another Pokémon that either has type advantage or can stall and set some traps for the rest of the battle.
I imagine the meeting where they came up with Rotom had a lot of people saying, "No, shut up, it's fine," to each other. It's a weird one, in a universe where the designers seem to keep trying to out-weird themselves.
Rotom is an electric/ghost Pokémon that is able to take possession of different machines. In Pokémon Sun and Moon, you probably know it extremely well, seeing how it's your Pokédex and all.
Rotom can take possession of machine parts and transform into them, which changes its Ghost typing to something else. It can be a space heater (Fire type), refrigerator (Ice), oscillating fan (Flying), lawnmower (Grass), or washing machine (Water).
If you couldn't tell, it's the washing machine one we're focusing on, because TYPE ADVANTAGE, YO.
Wash Rotom has exactly one weakness. One. That weakness is Grass. It just works out where every other weakness of Water and Electric overlaps with a resistance on the other side (for example, Water types are weak to Electric, but Electric types are resistant. Therefore, weakness nullified, standard damage).
Also, Wash Rotom nullifies its natural Electric weakness to Ground attacks by having Levitate. And Ground-type enemies are subject to getting Hydro Pumped right out of the building.
Wash Rotom isn't outstanding in too many ways, and the tradeoff for having only one weakness is that it also doesn't have a ton of resistances (only Ice, Steel, Flying, Fire, and Water). It's not going to win the whole fight for you, but it's a solid enough wall that it can actually deal some damage. You can also give it Volt Switch if you want to employ the same hit-and-run strategy as Pheromosa, but it doesn't have the speed to pull it off quite as easily.
Mimikyu just wants to make friends and sweep your whole team in the late game. And it's all out of friends.
Like Wash Rotom, Mimikyu gives you an advantage by having very few type weaknesses with its Ghost/Fairy typing. Only Ghost and Steel moves will hit especially hard, while it completely nullifies Normal, Fighting and Dragon moves. It also has a double resistance to Bug moves.
On top of all that, Mimikyu comes equipped with the ability Disguise. Disguise absorbs the first hit Mimikyu takes and nullifies the damage. This means you get a free turn to set up with Swords Dance, Agility, or whatever else you might need to get sweeping.
In a pinch, Mimikyu can also throw out a Pain Split, which can be a devastating blow against high-HP Pokemon and potentially act as a huge heal under the right circumstances.
While Mimikyu's stats may not stand out, it's a pesky opponent that can wreak a lot of havoc before it goes away.