The thirteen clothing brands in the game tend to name or decorate their pins according to one or more themes. Some pins will fall outside of the theme, but most of them follow the theme. The themes are as follows:
D+B has little in the way of a full theme, but they have a line of pins with the theme naming of "Sexy [something]". Their pins pins have glittery designs that use lots of purples and blacks, with heavy amounts of embossing and what appear to be rhinestones.
Natural Puppy has a huge line of pins that give happy, angelic-sounding names to their mind-bullet producing pins. Examples include Innocence Beam, One Love Magnum, Purity Launcher, etc. They also have the only set of Entanglement pins, all "[X] Me Tether". The pin designs are heavy on pastel colors and strong color contrasts. A good number of them have the silhouette of an animal on a solid-color background.
Pavo Real has a number of small themes, among pins that are not linked by evolution, but nevertheless have similar effects: some of their themes include "Strong [something]", "[Something] Factor", and the like. Their pin designs tend to look like glyphs carved in stone.
Mus Rattus has a lot of pins with an "[X] Warning" name, such as Shock Warning, Blast Warning, Teleport Warning, etc. They also have a line of pins with the name "Aqua [something]" or "Burning [something]", as well has having 'cartoony' Kawaisa designs. Several of these designs feature a mouse who seems to serve as the brand's mascot (he also appears on a few threads they sell, judging by the descriptions, where he's identified as Mowzy).
Jupiter Of The Monkey exclusively stocks pins with Japanese names. They tend to have the names of legendary weapons, as well, such as Kusanagi, Muramasa and Masamune. Fittingly, they are mainly Positive pins that have Neku attacking the enemy with psychic blades. The six sword-types spell out MONKEY when put in sequence. They also have an evolution line of Lance Lunge pins, also with Japanese names. At least up to "Shiro", the pins all have the Japanese words for 1 to 4 respectively, which is reflected in the pins' designs. The last seven or so designs (up to and including their brand pin) include various permutations on the brand's logo, and every pin adheres to the same basic color scheme with shades of purple, orange, and white.
Hip Snake has a few overlapping themes. Most prominent is a "look" theme, with pin names like "Sizzling Gaze", "Icy Stare", and "Eyes Full Of Light". Also, there is a seemingly unrelated pin, called "Long Live The Rock", which seems to only fit under the "Long Live The [X]" theme, also in Hip Snake, but if one looks at the pin's decoration, one realizes that the (petrifying) pin has the image of a Gorgon, which turns its enemies to stone with a look. Most of the pins also have at least somewhat of a star motif - in fact, only three of them lack it.
Under Sheep Heavenly, we have "[X] Squeeze", "Gimme Dat [X]", "[X] Leisure", and a number of pins with "Healing" in the name. The pins use bright primary colors, and all but one of the pins has a cartoony animal as part of the design.
Tigre Punks is one of the few that doesn't seem to have much of a theme outside of extremely small ones used in a few evolution chains. The pin art designs are heavy on oranges and blacks, with an emphasis on punk or grunge styles, featuring a lot of spikes, sharp details and splashed paint.
Dragon Couture has flowery names for the pins, usually including a comma, which tend to sound like proverbs (specifically, four-character proverbs, although there might be a preposition or similar as a fifth word), though they usually don't make much sense, but they do sound cool. Examples include "June Hearth, January Fan", "Follow Suit, Fall In Turn", "Self Found, Others Lost", and "Final Pyre, All Expired". The pins use very stylized, Chinese-esque drawings, each one hinting at the pin's power.
Lapin Angelique pins tend to either have an animal in the name, or the word "Lolita", or both. For example: "Lolita Chopper", "Circuit Spider", "Lolita Bat". Most of these, even when they don't refer to it directly, tend to have imagery associated with the Elegant Gothic Lolita theme of the brand - notably, many have a motif of a lace pattern prominently displayed.
Pegaso has a "Monarchy" theme, but it's really more of a Chess Motif. Examples include Aqua Pawn, Pegaso Bishop, Lightning Rook, Queen's Knight, Her Royal Highness, King Arthur, and Excalibur. Like Jupiter of the Monkey, they tend to have at least part of their logo visible in every pin design, often as something resembling a watermark. The pin designs are heavy on blues and whites, giving it a refined, royal feel with a modern high class flair.
Wild Boar has two themes: one is a large number of pins with names involving fire or explosions, and the other is a line of pins using skater and hip hop lingo, like Kewl Line, Dope Line, and Diss. The pin designs feature urban graffiti stylings, and contains a lot of writing. Five of its pins spell out "HEAVY" when put together.
Gatito, fittingly enough for a line of clothing made by the elusive CAT, decorates nearly all of its pins with CAT graffiti pieces. That, or the Gatito skull mascot. Some of the sets form a single piece when put together, like the Approaching Eden setnote Stylized yellow tiger or the Over The Topnote That weird cat throwing out the horns. Probably the most prominent CAT piece.
In addition, although unbranded, most of the pins with "Tin Pin" in their name have symmetrical, heavily stylized designs, as well as there being a group of pins that correspond to Final Fantasy summons.
Almost all of the Angel-class pins are named after an enemy type found in the game (Wolf, Frog, Cornix, etc.), and they all feature a white outline of that enemy type, on a solid black background.
In the game, despite there being pins up to 10,000 yen, a lot of special and rare items require a 5 yen pin, which is probably the rarest money pin in the game. This is actually culturally significant, as the Japanese for 5 yen, "go-en", is a homonym for fate or destiny, and is related to luck in that it is very commonly used in donations to Shinto shrines because of this reason.
Mus Rattus is of course, the mouse. The name Mus rattus was the former name for the black rat. In addition, plenty of its clothes give off a "cute" vibe.
D+B (Dangerous Bull) represents the ox. Some of its clothes are cowboy-themed to go with the bull, too. Club wear in addition to ice psyches also reference a belief that Ox signs that are born in winter are granted with a life of ease and little labor.
Take a wild guess as to what Tigre Punks symbolizes.
Dragon Couture obviously symbolizes the dragon. In contrast to Tigre Punks' grunge punk style, their clothing and pins are very Eastern-inspired. (Its main store is also in Hong Kong).
Hip Snake = snake.
If you know enough Greek Mythology, "Pegasos" was the name of a winged horse sired by Poseidon. Hence the brand Pegaso symbolizing the horse. (Being upper-class fashionable, its main store is in Milan).
Sheep Heavenly represents the sheep/ram, evident in its Moe clothes.
Jupiter of the Monkey represents the monkey, possibly also the legend of the Monkey King if you take into account that in Roman Mythology Jupiter was king of the gods.
"Pavo Real" is Gratuitous Spanish for peacock, but it translates literally to "Royal Chicken", making the brand Pavo Real representative of the rooster.
Natural Puppy is of course, representative of the dog.
And finally, the Wild Boar brand, which represents the pig if we're talking Chinese or the boar if we're talking Japanese. Featuring explosive psyches is a reference to the Japanese Zodiac, where Boar signs are believed to be dynamic and explosive in personality.
Last (and probably least) is the brand Gatito, itself being Gratuitous Spanish for kitten - hence the cat theme, not to mention being designed by CAT.
With the brands themselves also being based on the Chinese Zodiac, the brands, if deeply analyzed by a Chinese Astrology expert, have their styles clash against their respective worst incompatible romantic signs.
Mus Rattus vs Pegaso, being humility, with cheap but affordable and common clothing, versus luxury, high priced watches, accessories, and suits that are unavailable with your first wallet.
D+B vs Sheep Heavenly, being sexiness, through skin tight club wear, bikinis, and boots, versus innocence, through Sheep Heavenly's kawaii style aesthetic.
Tigre Punks vs Jupiter of the Monkey, being the underground, with rebellious punk rocker wear, leather jackets and grunge memorabilia, versus the mainstream, JOTM featuring hip clean cut and stylish uptown modern urban wear dedicated to keep with the future styles of Shibuya.
Lapin Angelique vs Pavo Real, being the look, with gothic lolita wear with clothing features that are more for show and beauty, like asymmetrical threads, tall platform shoes, and dresses (and with the "Jinxed" abilities considerably), versus function, jewelry that is compact, subtle, yet ever out of the way and granting considerable bonuses.
Dragon Couture vs Natural Puppy, being flamboyance, with styled shoes, t shirts and extravagant dresses and clothes, versus simplicity, with rather subtle and one color clothes, and pins that feature simple designs.
Hip Snake vs Wild Boar, being the old and culture filled, with nostalgic American 1970's era clothing and accessories, versus the new, cool, yet still coming to fruition, with 1990's and 2000's era hip hop and skater threads and pins with a graffiti affluence.
In the Chinese calendar the snake and dragon are right next to each other. This may be a reason for Megumi having both them as his noise forms.
One version of the legend of the Zodiac has it that the Chinese decided to base their calendar system around the first twelve animals that crossed the river Zodiac which was said to be a rather difficult river to cross. Two of the animals that wanted to cross were the cat and the ox. They both faced problems though, as the cat was not strong enough to cross the river while the ox's vision was poor. Seeing this, the rat came to them and suggested that they work together with the ox letting them ride on his back and the cat acting as the ox's eyes. This worked well but just before the end, the rat pushed the cat into the water making and hence it did not become part of the Zodiac while the other two did. This may be the reason for the thirteenth brand and CAT. In further reference to this is during day seven with Joshua, only Mas Rattus (rat) and D+B (bull) pins are allowed to be used on certain floors.