Kanto Eevee
Just your good ol' eevee, living their best life.
[LOCATION: Starter & Catch]
Noir Eevee
A dark-furred eevee with charchoal chest fluff.
[LOCATION: Starter]
Vanilla Eevee
A light-furred eevee with alabaster chest fluff.
[LOCATION: Starter]
Shiny Eevee
A pretty rare Pokémon!
But just as cuddly and loving as any other eevee.
[LOCATION: Catch, Diving, & Shrine]
Variant Eevee
These eevee have markings that can cover up to 90% of their bodies.
Each eevee can have multiple coloured markings.
These colours include: 
Black, Brown, Beige, Cream, White, Grey
When they evolve, the range of colours of their markings are shades similar to their evolutions.
[e.g flareons would have a range of brown, yellow, red, and orange. espeon would have white, gray, purple, and pinks.]
[LOCATION: Catch, Diving, & Shrine]
Domestic Eevee
These eevee have markings that can cover up to 90% of their bodies.
These markings can be any colour, and each eevee can have multiple coloured markings.
[LOCATION: Breeding (Coloured + Variant)]
Melanistic Eevee
These eevee have completely black fur, even their tail marking can't be seen! Their evolutions are also melanistic.
[LOCATION: Catch, Diving, & Shrine]
Albino Eevee
These eevee have completely white fur, even their tail marking can't be seen! Their evolutions are also albino.
[LOCATION: Catch, Diving, & Shrine]
Coloured Eevee
These eevee can be found in any colour!
They don't have any additional markings alone, but some may have the Variant or Domestic trait too.
[Their evolution must be a similar/identical shade.]
[LOCATION: Catch, Diving, & Shrine]
Luminous Eevee
These eevee have glowing markings that can cover up to 90% of their bodies. Markings can be any colour.
[Basically a Domestic Eevee but with glowing markings.]
[LOCATION: Diving & Shrine]
Fluffed Eevee
These eevee have long, fluffy fur!
[There is no maximum floof, go wild. Even vaporeon will have long fur!]
[LOCATION: Catch, Diving, & Shrine]
Piebald Eevee
These eevee have patches of white fur!
[LOCATION: Catch, Diving, & Shrine]
Patches Eevee
These eevee have patches of black fur!
[LOCATION: Catch, Diving, & Shrine]
Chimera Eevee
These eevee are chimeras! Each 'side' can have their own mutations and traits, one can cover up to 90% of the eevee.
[LOCATION: Catch, Diving, & Shrine]
Familiar Eevee
[Suggested by Sharklestial!]
These eevee seem familiar...
These Pokémon can have fur, ear, and tail mutations, markings, and colours that resemble any mammal except hooved or aquatic mammals/humans or human-like primates! ie. canines, felines, rabbits.
[When they evolve, they must retain the general look, but unnatural colours are allowed for eeveelutions with this mutation.]
[LOCATION: Charm Bell]
Angel Eevee
These eevee radiate a reassuring aura.
These eevee are often pale in colour. They can have light coloured/gold markings. Angels also have a halo and/or feathered wings.
[LOCATION: Light Tome]
Demonic Eevee
These eevee radiate a chaotic aura.
These eevee are often dark in colour. They can have dark coloured/red markings. Demonic eevees also have horns and/or leathery wings.
[LOCATION: Ominous Book]
Crystalline Eevee
These eevee are covered in sparkling crystals!
The crystals can take any colour. Crystals may cover entire body, in fact, some eevees are completely made of crystal.
[LOCATION: Diving & Shrine]
Shade Eevee
These eevee have a dark aura that can cover up to 90% of their bodies.
[LOCATION: Catch, Diving, & Shrine]
Giga Eevee
These eevee have features that may be bigger than a normal eevee's.
[i.e bigger ears, tail, frills for a vaporeon, horn-like gem for espeon.]
[LOCATION: Catch, Diving, & Shrine]
Spiky Eevee
These eevee may have horns, spikes, quills, and/or spurs.
[LOCATION: Shrine]
Multi-tail Eevee
These eevee have multiple tails! [Tail length can be modified.]
[LOCATION: Catch, Diving, & Shrine]
Winged Eevee
These eevee have wings! [Wings can be anything, i.e leaves, feathers, fins.]
[LOCATION: Shrine]
Elemental Eevee
These eevee are made of a certain Pokémon type. They are coloured/can have markings coloured similar to their type's colours.
[i.e water elemental causing them to be fully liquid, dark elemental with shadows etc.]
[LOCATION: Sparkling Crystal]
Sprite Eevee
These eevee are partially made of an element. Unlike Elementals, they can be made of any type, not just their own.
[LOCATION: Diving & Shrine]
Pixie Eevee
These eevee are tiny! They're usually a light/pastel colour and can have any pastel coloured markings.
Pixies can have any type of insect/fairy wing.
[LOCATION: Shrine]
Statue Eevee
These eevee can be made of stone, ceramic, wood, etc. They can have any markings, some may also have cracks.
[LOCATION: Infusion]
Android Eevee
These eevee are androids! They can be modified in any way, i.e adding light markings, visors, etc.
Must look mechanical, synthetic fur is allowed but not for the entire body. Steampunk-styled machinery also allowed!
[LOCATION: Infusion]
Snacks Eevee
Don't eat these eevee! They can have any mutation as long as they are based of/made of a certain food!
[LOCATION: Infusion]
Plush Eevee
These eevee are made of plush! They can have stickers, decorations, windup keys, etc. and can be any colour!
Markings cannot be gradient, each marking's borders must be clear and/or marked with stich lines.
[Usually not particularly furry.]
[LOCATION: Infusion]
Aquatic Eevee
These eevee are built for the waves! They have aquatic tails and fins for ears. (Or ears tipped with fins/ears with fins beside or behind them!)
They can be any colour, but their markings are limited to stripes, gradients, and scale markings.
[LOCATION: Diving]
Draconic Eevee
These eevee are quite fierce! They have scaly wings, horns and a draconic tail. [Horns and scales optional.]
Unlike Demonic Eevee, they can be any colour and can have any markings.
[LOCATION: Diving & Shrine]
Skybound Eevee
These eevee have talons, wings, and feathery tails! They can have any colours/markings [excepting neons] and can have additional crests.
[LOCATION: Shrine]
Mermaid Eevee
Where's the other pair of legs? These eevee are mermaids! They can have any colour or markings as long as they're colourful.
(i.e more than three colours.)
[LOCATION: Diving]
Serpentine Eevee
These eevee have serpentine tails and eyes!
They can have any colour or markings but are limited to the following colours:
[LOCATION: Diving & Shrine]
Unicorn Eevee
These eevee look pretty magical! They have unicorn-like horns, hooves, and/or tails.
Unicorn Eevee can only be natural horse colours, but may have markings of any colour that can cover up to 90% of their bodies.
[LOCATION: Diving & Shrine]
Korok Eevee
These eevee sorta appeared out of nowhere! They can have any type of leaf covering their faces and root-like or plant-like horns.
They can only have woodsy colours (red, brown, white, beige, etc.) and their leaves can be any existing leaf colour.
[LOCATION: Korok Seed]
Seraph Eevee
These eevee are said to be blessed by celestial beings.
Usually downy and winged, can have any colours and/or markings. [Must have some sort of x-motif on them.]
[LOCATION: Solar Gem]
Moonblight Eevee
By absorbing moonlight, they are able to temporarily shift into an incorporeal, misty form.
They have wispy appendages, can have any colours and/or markings. [Must have some sort of star motif on them.]
[LOCATION: Lunar Gem]
Starlight Eevee
Fortunately, these eevee won't scorch your hands when petting them!
They're made of actual light, can have any colour/markings and little star-like particles float around them.
Star Bunny Form
All Starlight Eevee has a Star Bunny form! They're bunny-like in appearance, but can also have any mutation/markings as long as they're star-themed and still resembles their original look.
[LOCATION: 'Bits of Starlight' Event]
Delta Eevee
These eevee have typings they aren't usually found with! These typings influence the markings and look of the eevee.
When these eevee evolve, they can either retain only their delta type or gain the type of their evolution in addition to the former.
[LOCATION: Delta Ball]
Error Eevee
These eevees' lack of traits cause them to 'glitch' out. They can be one solid colour.
Apparently, this trait is nothing more than a visual effect as Error Eevee act like regular ones!
[LOCATION: Removing Kanto Trait]
Gaia Eevee
These eevee have mutations and traits that resemble plantlife!
They can have any colours, markings, and/or mutations as long as they resemble plants.
[LOCATION: Shrine]
Slime Eevee
These eevee can only have one colour or a gradient, but they can also have glowing markings.
They can also have things like spikes, gems, stuff floating around them, etc.
[LOCATION: Slime Pudding]
Paper Eevee
These eevee are made of paper! Thus they can have any colours/markings.
Can be magazine cut-outs, origami, etc.
[LOCATION: Infusion]
Aura Eevee
These eevee have floating objects surrounding them. Can be crystals, hearts, petals, etc.
[LOCATION: Aura Potion]
Cartoon Eevee
These eevee are cartoons come to life, reminiscent of the rubberhose style and are usually only black and white in colour.
[LOCATION: Infusion]
Coral Eevee
These eevee are usually found in aquatic biomes, covered in coral of any colour.
[LOCATION: Diving]
Glass Eevee
These eevee are made of glass. They can have any markings, some may also have cracks.
[LOCATION: Infusion]
Mini Eevee
These eevee have features that may be smaller than a normal eevee's.
[i.e smaller ears, tail, frills for a vaporeon, fur for a flareon.]
[LOCATION: Catch, Diving, & Shrine]
Void Eevee
These eevee are made of some sort of dark mist.
[any colours allowed but must not be too bright]
[LOCATION: Secret Lab]
Fireworks Eevee
These eevees' fur somehow display moving markings resembling fireworks!
[any colours allowed]
[LOCATION: 'Dynamite Giveaway' Event]
Toy Eevee
These eevees are toys come to life, like legos, wind-up toys, dolls, etc.
[LOCATION: Infusion]
Pixel Eevee
These eevees are somehow pixelated?!
Their colours and markings works as a Coloured/Variant Eevee, though some Pixel Eevee also glow!
[LOCATION: Arcade]
World Eevee
These eevees contain mini biomes in them! Must be natural occuring biomes unless they have additional traits.
[LOCATION: Infusion]
Time Eevee
These eevees are born of memories. Their fur somehow display a short, repeating scene!
[LOCATION: Arcade]
Chao Eevee
These eevee have small wings and a single object floating above their head. Chao Eevee can be any colour/have any markings and can switch between Neutral, Dark, and Hero alignments.
[They can also have mutations akin to official chao.]
[LOCATION: Arcade]
Darling Eevee
These eevee have sylveon bows and any markings but are always a red/pink-ish hue. (Saturation is not limited!)
These eevee aren't limited to evolving into sylveon, but when evolving into other eeveelutions, they will carry over their limitations.
i.e The bow and the colouring.
[LOCATION: 'Picnic' Event]
Choco Eevee
These eevees have beaks, talons, and a fan-shaped, feathery tail.
Their colours and markings works as a Coloured/Variant Eevee, and they can be any chocobo colour.
[LOCATION: Arcade]
Alpha Eevee
These eevees are usually bigger and more aggresive than their counterparts. They can be identified from their glowing eyes and wild fur.
Their colours and markings function as a Kanto/Variant!
[LOCATION: 'Reserve' Event]
Chicken Eevee
[Wished for by Kip!]
These eevees can have any mutation/colour as long as they resemble a real-life species of chicken.
[LOCATION: McMeda]
Primal Eevee
These eevee are an ancient breed, revived from fossils!
These Pokémon can have any mutations as long as they resemble any real prehistoric creature species. Their colours must be natural-looking.
[LOCATION: 'Dig Site' Event or McMeda]
Musical Eevee
These eevee can sing beautiful melodies!
They may be surrounded with a strand of musical notation or have them as markings. They can have one mutation relating to a musical intrument.
Can only have colours in the following range even when evolved:
Black, Brown, Beige, Cream, White, Grey
[LOCATION: Shrine]
Hive Eevee
[Wished for by Smolbot!]
These eevees are permanently bonded to one another, and can even fuse together!
They gain levels together but have separate traits and names.
[LOCATION: McMeda]
Alien Eevee
[Wished for by catspiracy!]
These eevees come from outer space! They can have multiple limbs and can only be neon-coloured!
[LOCATION: Catch]
Idol Eevee
[Wished for by Rubwee!]
These eevees have certain symbol motifs unique to them, like hearts, diamonds, etc. and have long ear-like appendages.
These eevees are monochrome, only allowed up to 15% of other coloured markings.
[they can also have fur and tail mutations]
[LOCATION: Shrine]
Vessel Eevee
[Suggested by Uridove!]
These eevees seem to be made of a void-like matter...
They have cloaks and horns that can be any shape.
[LOCATION: Arcade]
Dream Eevee
[Wished for and examples designed by StormJay!]
These eevees seem to always have their heads in the clouds...
This trait makes their base colour lighter and gives them an additional Variant effect.
Dream Eevee have some parts of them made of clouds of any colour.
[LOCATION: 'Dream Bridge' Event]
Hellbat Eevee
[Brought to you by the Alchemist Union!]
A little dash of vampiric essence, a sprinkle of demonic souls. Hellbat Eevee are crafted with alchemy.
Their demonic essence allows them to be bonded to spellweavers with runic contracts, and their vampiric essence means these little imp-like creatures already come with vampiric forms! To come into being, Hellbat eevees are always marked with their contracted runes, which means they're always bound to someone!
Hellbat Eevee have bat-like wings and ears; they function similarly to Demonic Eevee!
They also have a Vampire Form and usually rune-like markings.
[LOCATION: Breeding (Familiar+Demonic)]