Most Pokémon fans learn early on that evolution is the key to obtaining the most powerful Pokémon. Training and evolving your young Pokémon into higher stages comes with several benefits including higher stats, new moves, and some different or additional typings. As a result, most Pokémon are utterly useless in their lowest forms.
There are several exceptions, however, as many items and strategies in the game have made some unevolved Pokémon just as powerful as their later evolutions, and in some circumstances, they can be even more competitively viable than their fully-evolved peers.
10 Porygon2
Porygon2 has been a classic unevolved staple of competitive Pokémon for several generations. With its third evolution Porygon-Z, this species becomes an incredibly strong sweeper with a slightly subpar speed, but while it stands out among other Normal-types it has some lackluster speed and defenses.
Porygon2 naturally has some stronger defensive stats than Porygon-Z while still having some sufficient offense. It learns a wide range of moves like Recover and Trick Room to help it keep powerful, but also many offensive moves of various types like Thunderbolt and Ice Beam. It’s more of a tank than a glass cannon, but has far better all-around stats than most other defensive Pokémon.
9 Dusclops
One of the greatest ways to use an unevolved Pokémon in competitive play is through the use of an Eviolite, a held item introduced in Pokémon Black & White that gives fifty percent more Defense and Special Defense to the wielder. This works on any Pokémon with a later evolution, but many can exceed the defenses of their later forms.
Porygon2 is a great classic user of this item, but others will always need this item to stand up to fully-evolved Pokémon. This includes Dusclops, another classic unevolved staple of competitive play. Not only are its defenses ludicrous with the Eviolite, but its access to attacks like Night Shade and Will-O-Wisp also make up for its low damage. Add in a Trick Room to make up for its lost speed, and it becomes nearly invincible.
8 Galarian Corsola
Thanks to the Eviolite, nearly every unevolved Pokémon of each game is often a contender for competitive play. Not every Pokémon can make the cut, but if they have some strong defenses or strong recovery moves they can often make for powerful supportive teammates, especially in double battles.
The new Ghost-type Corsola from Pokémon Sword & Shield is one of these thanks to its access to the rare move Strength Sap. This move both lowers an opponent's Attack stat and recovers health equal to the target’s original Attack stat. With high enough initial defenses, it can keep using this attack to fully remove any physical attacker’s offensive power.
7 Chansey
Another bulky and classic Eviolite user is Chansey, whose defenses are relatively unique compared to the other Pokémon of this list. While it has massive Special Defense and a maximum HP value that rivals Blissey, its physical Defense is still quite disappointing, even with an Eviolite equipped.
What makes up for it is its wide set of other unusual defensive skills. Softboiled makes for a great way to recover an obscene amount of health, while abilities like Natural Cure provide an ability to get rid of status ailments like Paralysis and Poison that other tanks would be whittled down by.
6 Scyther
Scyther might be one of the few unevolved Pokémon with a wide variety of builds. While some are forced into being defensive tanks or aggressive fighters, Scyther has some all-around high stats. Its defenses with an Eviolite can rival many fully-evolved tanks like Bronzong, but its Attack and Speed also make it a surprisingly bulky attacker.
However you build it, it certainly doesn’t need to evolve into Scizor to be powerful. Scyther’s one weakness is its Bug and Flying-type combination that provides a large variety of weaknesses compared to Scizor only being vulnerable to Fire-type moves, but it can otherwise do tons of things that Scizor can’t.
5 Doublade
One of the more notorious Eviolite users was Doublade, a Pokémon that has more Defense than a Steelix while holding an Eviolite and while still maintaining more physical damage than many faster sweepers. It lacks speed, but once put in a Trick Room or against most physical attackers, Doublade can often come out victorious in most matchups.
The prime advantage to Doublade over Aegislash is that it lacks Aegislash’s ability to swap between offensive and defensive stances. This can make Aegislash difficult to handle, but Doublade has great physical power while still maintaining the defenses much more consistently than Aegislash.
4 Riolu
Riolu is a relatively new member of this list, largely thanks to the Isle of Armor's new move tutor in the Master Dojo. His new Fighting-type move, Coaching, might seem subpar, as it simply increases the user’s Defense and Attack stats, but in Double Battles it also will boost the teammate’s stat at the same time.
What makes Riolu an unusually great user of this move is its ability Prankster, which lets all Status Moves go first in a battle. This way, it can provide a stat boost before a speedy teammate takes its turn, giving a spectacular boost to help the partner annihilate its target while growing more defensive. Adding a Focus Sash lets it avoid fainting in a single hit, giving it a little extra sturdiness to survive more than one turn.
3 Cottonee
Another fantastic Prankster user is Whimsicott, as it gains several Status Moves like Tailwind and Cotton Guard to provide tons of support in Double Battles. That said, its defenses aren’t that much more significant than its lower form Cottonee, so it can be just as effective to use this weaker evolution if you want some pure support.
Cottonee also benefits from low health, as it means any attack can bring it to a single health point while holding a Focus Sash. This can be great because Cottonee can learn the move Endeavor, which can make a target’s current health identical to the users. This lets it do tons of damage while providing all kinds of utilities that most Pokémon can't use as efficiently.
2 Pikachu
As the mascot of the series, it only feels right for Pikachu to have some competitive skills, and it gains tons of tools with every new game. There are several strong attacks it can learn that are both physical and special, giving it tons of diversity alongside a great neutral speed stat, and with Pokémon Sword & Shield it even gains an adorably husky Gigantamax form.
Using it in competitive play requires some immensely high stats, but thankfully those can be provided with a held item called the Light Ball. This will double the stats of any Pikachu holding it, meaning its offensive stats can contend with some of the strongest Pokémon, just like in the anime.
1 Clefairy
One final Kanto Pokémon with competitive use is Clefairy, who appears quite similar to Chansey on the surface. It has some slightly low defensive stats but features some massive HP and a wide variety of moves to give it both offense and utility. This, alongside being a Fairy-type, makes it a fairly unique tank that fits into a lot of teams.
That said, the reason it stands above its evolved form Clefable is not in its ability to hold an Eviolite. The key way to use Clefairy is in a Double Battle with its unique Hidden Ability, Friend Guard, which protects its teammate from a quarter of all damage it would normally take. Clefairy can be a strong tank on its own, but by adding to an ally’s defenses it makes them both hard to take them down.