There are so, so many Pokémon these days that it can sometimes be hard to keep track. And they just keep adding more. Not that we're complaining, of course. But the addition of more Pokémon doesn't just make it harder to remember them all. It also makes it harder to pick your beloved teammates.
Of course, you can worry about party balance and having your Pokémon cover for each other's weaknesses. Or you can be a real trainer, pick one type, and stick with it for the rest of your life. How else will you become a gym leader? If you're having trouble deciding, why not consider your D&D alignment, and choose based on that?
9 Lawful Good: Fighting
If you consider yourself Lawful Good, that means you believe that the best way to accomplish good in the world is through fighting honorably and enacting justice. The guilty must be punished, and this good can only be achieved through commitment and discipline.
This makes Lawful Good a perfect match for the Fighting type. Fighting-type Pokémon get their extreme strength through disciplined training and wholeness of mind and body. The designs of many Fighting Pokémon are based on the heroes of martial arts movies. Their inherently heroic nature makes them a good fit for would-be heroes of justice.
8 Neutral Good: Psychic
On the other hand, if you're Neutral Good that means you believe in doing good for goodness' sake. You don't have a strict code of honor you're trying to uphold, and neither are you fighting for some great cause. Instead, you're just willing to lend a hand to someone in need. You're more concerned with alleviating suffering than punishing the ones who cause it. If this sounds like you, maybe consider training up some Psychic-type Pokémon.
This might sound odd at first because not all Psychic Pokémon are inherently good. But what they are is sensitive. Psychic Pokémon are tapped into the emotions of those around them. They'd be a good choice for your team if you're also a naturally sensitive and compassionate person.
7 Chaotic Good: Fire
Chaotic Good characters are those that embody a desire for goodness and justice but don't care what society or the law has to say about their methods. You'll often find Chaotic Good represented in media as freedom fighters, revolutionaries, and vigilantes. They do good at any cost and run headlong into dangerous situations because their conscience demands it.
They highly value independence, but can also be somewhat selfish. In honor of the fiery spirit of Chaotic Good, they were matched with Fire-type Pokémon. Fire Pokémon are often said to have tempers that match the flames they control and don't have much time for self-discipline. But Fire is also one of the types you can choose as your starter in every game, and what are you if not the hero, ready to put those flames to good use?
6 Lawful Neutral: Rock
If you believe in law and tradition above all else, you're probably Lawful Neutral. Neutral alignments don't much care for the welfare of individual people over the welfare of society at large. A Lawful Neutral person always keeps their world, behaves with honor, and acts in accordance to their tradition.
However, they run the possibility of being too strict and allowing an unjust law to stand unopposed. Lawful Neutral is best represented by the Rock-type. Rock Pokémon are sturdy and reliable. They can survive extreme conditions and come out whole. Rock Pokémon, like Lawful Neutral people, are unyielding.
5 True Neutral: Grass
True Neutral is about balance. Good and evil, law and chaos, those are all extremes. Letting the world tip too far into any extreme is dangerous. Neutrality is the key to keep the world healthy and diverse. True Neutral is the alignment of most beasts, who simply act according to their nature.
However, it's also the alignment of most druids, who seek to keep the civilization in harmony with nature. And what could be a better partner for a druid than a Grass-type Pokémon? Grass Pokémon are nature incarnate. They tend to the natural world like diligent gardeners, keeping things growing and changing, never letting one thing stagnate. If balance had a type, it would be Grass.
4 Chaotic Neutral: Fairy
A Chaotic Neutral character values many of the same things a Chaotic Good one does, with one crucial exception. They don't care for anyone's personal freedom except their own. They don't necessarily want to hurt anyone, but they definitely want to make sure they get their share of the pie. Who better to represent these selfish, merry individuals than the Fairy type? Fairy Pokémon are based on the myths and legends of fae creatures in our own world.
Most don't harbor any particular malice for humans, but instead view them as little more than playthings. They love to play tricks, confuse, and deceive but it's all in good fun! For the fairy at least. Fun is what they care about most.
3 Lawful Evil: Ghost
Now, hopefully you're not evil, but we're not here to judge you if you are. Evil-aligned characters actively seek to cause harm to promote their own agendas. Lawful Evil characters in particular seek to build their power base at the expense of anyone who gets in their way.
They follow the rules, but the also tend to be the ones making the rules in the first place. Ghost-type seems like the best fit for these diabolical masterminds. Ghost Pokémon have to abide by the rules of their, often strange, existence as partially-corporeal beings. They take what they want from the living, but usually only if the living trespass on their territory or offend them in some way.
2 Neutral Evil: Poison
Neutral Evil characters don't have much of a care for law and order, positive or negative. Instead, they do whatever they want. They could go days without hurting anyone, but if the right mood strikes them they could burn down a house, beat up an old lady, or steal candy from a baby. What matters is what they want and what they can get out of you.
Poison-type Pokémon are probably the best partners for these dangerous individuals. Back before Dark-type existed, Poison was the evil Pokémon type. It was used almost exclusively by members of Team Rocket and poison is a destructive ability, that weakens and breaks down those affected.
1 Chaotic Evil: Dark
Chaotic Evil is the worst of the worst. They're not so much invested in their own interests as much as they are ruining everyone else's. They tend toward wholesale and random destruction. They relish the pain of others. And most of all, they love to break the rules. In that spirit, Chaotic Evil and Dark-type Pokémon (or more literally translated: Evil-type) are a match made in hell.
Dark-type Pokémon fight dirty. They're the polar opposite of the Fighting-type, and Fighting Pokémon even have a mechanical advantage over them in the games (because the good guys always win). Dark Pokémon disdain honor and prefer sneak attacks or unfair numbers. They want to win and winning means destroying everything in sight.