Let’s start this list with one of the Eeveelutions from Generation II, Umbreon, the dark type evolution of Eevee that resembles a black fox. Umbreon is the first dark-type Pokémon in the Pokédex and it was the only pure dark type of its time, but now is one of nine others. In Japanese, its name is Blacky, possibly referring to black cats, as they are considered lucky in Japan. Its first Pokédex entry found within the Pokémon Silver Pokédex states that:

‘When darkness falls, the rings on the body begin to glow, striking fear in the hearts of anyone nearby.’

We think that Umbreon is one of the coolest shiny Pokémon because of the color its rings change into. Blue, generally speaking, is a cool color and when mixed with black, it makes Umbreon even more mysterious. During the night, only its rings appear from within the darkness, which is what makes Umbreon a rather cool Pokémon indeed. A shiny Umbreon also has oval shaped pupils that are of its former yellow color.

Up next is the Pokémon Yveltal that was introduced in Pokémon Y as part of Generation VI. Yveltal is a Dark/Flying type and is the only dark type legendary Pokémon. It is the counterpart to Xerneas and represents ‘destruction’. Its design appears to be based on Norse mythology as one of the guardians of the Yggdrasil trio. Yveltal has the signature move Oblivion Wing, which no other Pokémon is capable of knowing. It’s Pokédex entry states:

‘When its life comes to an end, it absorbs the life energy of every living thing and turns into a cocoon once more.’

The shiny form of Yveltal has a white and red color palette. Its neck fur also changes to a darker gray to contrast the lighter colors. The color scheme makes it look like a skinless creature made of just bone and muscle, which is rather scary. However we think he is one of the cooler looking shiny Pokémon because of its exclusivity, that and Yveltal also resembles two strips of bacon or even a red velvet cake.

At number 8 on this list, is the tree-looking Pokémon; no, not Sudowoodo… Trevenant. A Ghost/Grass dual-type Pokémon that is made up of what appears to be a ghost possessing a tree. Trevenant is able to control trees using its root legs like a nervous system and is the only Pokémon capable of learning the move Forest’s Curse.

Trevenant is the protector of the forest and it is kind to the creatures that live within it. However, when it’s home is threatened, Trevenant will use the forest to trap the intruders and not allow them to leave. Trevenant’s design was based on Kodama, spirits that inhabit trees according to Japanese folklore, and loosely on the Japanese Kanji for wood.

Trevenant’s shiny form contains white bark with red leaves, like a birch tree with autumn leaves. It also has a purple colored eye. We think this makes Trevenant look much scarier and cooler because he more closely resembles a ghost and appears out of place among the other trees around it, making it a true terror to be avoided within the dark forest.

Introduced in the new 7th generation, and the legendary for Pokémon Sun. Solgaleo, a Psychic/Steel dual-type large lion. It is one of the only legendary Pokémon that is part of an evolutionary chain. Solgaleo has the unique move Sunsteel strike. It’s Pokédex entry states:

‘It is said to live in another world. The intense light it radiates from the surface of its body can make the darkest of nights light up like midday.’

Its shiny form is locked from within the new games, but their shiny forms were leaked prior to the release of the game. Solgaleo changes from white to red and the parts that are orange, the shards on his mane and the bands on his legs, change to purple. We think Solgaleo is one of the coolest shiny Pokémon because of how much more fearsome he looks when he’s red, almost like an angrier version of itself.

Next is Mega Gengar, a Ghost/Poison dual-type Pokémon that is the Mega Evolution of one of the original 151 Pokémon back in Generation I. Gengar’s type is unique as there are no other Pokémon with the same combination. Its mega form was only available after the release of Generation VI when they introduced Mega Evolutions.

The concept behind Gengar’s original design is that it was made to resemble a human’s shadow, lurking in the darkness hidden as someone’s shadow. While Gengar’s shiny is rather plain and isn’t much different to the original, Mega Gengar’s shiny version, is much cooler. It rocks a white with a pinkish tint color scheme and dark gray eyes making it resemble a ghost rather than a shadow. We think this contrast and combination of colors is what makes Mega Gengar one of the coolest looking shiny Pokémon. If you ever get your hands on one, be sure to give it a Gengarite!

At the midpoint of this list is Mega Metagross, another Mega-evolution Pokémon. Mega Metagross is a Steel/Psychic type and is known for being the heaviest non-legendary Pokémon. Metagross is a fusion of two Metang, which is a fusion of two Beldum, making Metagross the only Pokémon with 4 brains. It is one of the most intelligent Pokémon due to its brains’ ability to connect and process information like a super computer. Its design seems to be based on some form of a super-intelligent robotic, spider-like alien.

Its body changes from blue to silver and the silver cross on its head changes to gold as well as it’s claws and spikes, turning from a plain blue rock into a shining steel-like robotic beast. We think it looks even deadlier with its shining color scheme and it certainly looks like a Pokémon that no one wants to mess with.

Coming in at number 4 is Aegislash, a unique Steel/Ghost type Pokémon that resembles a royal sword with a shield. It has a distinctive ability known as stance change, which allows it to switch between an offensive and defensive position within battle and it is the only Pokémon capable of learning the move King’s shield.

We think that Aegislash’s shiny form is definitely one of the coolest out there because of its fearsome looking color palette that vastly changes in comparison to the original. Aegislash’s head changes from light gold to light silver and its body changes from gold with light silver edges to a steel colored body with red edges. Aegislash’s cloth-like hands change from purple to gold and its shield turns from a light gold to the same gray as its head; its eye also changes from purple to yellow. We think it looks more like a royal sword with the red and gold combination.

On the 3rd place on this list is Greninja, a Water/Dark type frog-like ninja Pokémon. Greninja has the highest base speed stat of all starter Pokémon and all of the water types. It is able to acquire the versatile hidden ability ‘Protean’ that only it and Kecleon are able to have, which allows the Pokémon to change types to the type of move it is about to use during their turn of a battle. Greninja’s design is loosely based on the Japanese folk story ‘The Tale of the Gallant Jiraiya’, which is about a ninja who could transform into a large toad.

Greninja’s shiny version is mainly black with a dark-red tongue-scarf and the lighter yellow parts of his ears, face, chest, and webbing become a dark gray, making it resemble a ninja that we know of today even more. Greninja’s eyes also become a darker red. This color scheme makes Greninja looks stealthier, mysterious and a lot cooler than its original colors, so that's why we think Greninja is one of the top shiny Pokémon in the series.

Our runner-up for this list is the Mega Evolution of one of the first original Pokémon, Mega Charizard Y to be exact. Charizard is a Fire/Flying type dragon that is the mascot of the very first Pokémon game, Pokémon Red. It is one of the most popular Pokémon chosen by fans from all across the world and it’s the first Pokémon ever to appear in the Japanese version of the anime. Mega Charizard Y has the highest special attack stat of all fire-type Pokémon and non-legendary flying types.

When shiny, Mega Charizard Y becomes a dark purple/gray color with red undersides on its wings. Taking the look of a dark/evil dragon, it looks more medieval with this particular color scheme and is one dragon to be feared indeed. We think that Mega Charizard Y is one of the coolest simply because of the fact that Charizard alone was one of the coolest original Pokémon, however, as a mega shiny it looks so much more awesome.

And the coolest shiny of them all is…Rayquaza, the legendary of Pokémon Emerald from Generation III. Rayquaza is a Dragon/Flying type and is the only Pokémon able to Mega Evolve without a mega stone, its Pokédex entry in Alpha Sapphire states:

“It flies forever through the ozone layer, consuming meteoroids for sustenance. The many meteoroids in its body provide the energy it needs to Mega Evolve.”

Rayquaza is apparently based on the Hebrew legends of Ziz, an ancient master of the sky. Rayquaza’s shiny form is undeniably one of the best ever seen in the series, as the color combination works really well with the concept and design of the Pokémon itself. Instead of the standard green we’re used to seeing, its body is of a cool jet-black color that contrasts perfectly with the brighter markings along the length of it. Almost like an Umbreon, Rayquaza rocks an even more mysterious vibe, having a primal, yet futuristic kind of appearance.