Evolution is a messy process. In real life, it leads to as many dead ends as it does new avenues. In Pokémon, it is typically a straight line, a series of checkmarks on the path to power. Typically. But you know what they say—rules are made to be broken.
You wouldn't expect one fluffy little fox to be such a bad boy, but Eevee was the original rulebreaker. Whereas most Pokémon only get a single forward path to progression, Eevee's split off into three branching lines. Later on that number would multiply, but even from the beginning, there was a lot of Eevee to go around. The different Evolutions (Jolteon, Flareon, Vaporeon) had such a variety of designs and aesthetics that they could have formed a boy band between them.
Having evolutions of different elemental types also makes it easy to see the different niches and gimmicks of them in action. What makes a Fire card a Fire card, and how is it different than Water?
The original quartet of cards featured the delicate linework and fairy-tale backgrounds from artist Kagemaru Himeno. It gives the creatures an otherworldly quality. With the exception of Jolteon's brazen challenge towards the audience, the rest are detached, aware they are being observed and unbothered by it. Every card also carries Quick Attack, which is a neat tying theme and a perfectly useless attack.
The Eeveelutions are also a perfect case study in the early archetypes that each energy type had. Water was about stockpiling, Lightning was about risks with possibly high rewards, and Fire was about burning through resources.
Following up their initial debut, the Eevee-trio took a walk on the dark side with their Team Rocket incarnations. These versions were lightweight and easily knocked out, but able to do quite a bit of damage in the meantime. An ongoing trend with the three is that Vaporeon is usually slightly beefier health-wise than the other two. Must be that subcutaneous layer of fat. They follow the same trend of Flareon being a heavy hitter, Jolteon being fickle, and Vaporeon being a scheming little rat. The art is also richly detailed, each creature darkly detailed and a far cry from their friendlier earlier versions.
Neo Discovery has a notable Eevee appearance. The little fuzzball appeared sans its three mainstay evolutions, but it had a power that would show up again and again on Eevee cards throughout the ages with a few tweaks here and there.
Energy Evolution was a hack to get this Pokémon to evolve early, almost like a built-in Trainer card. It also opened up deck construction a little, allowing players to more confidently slot in additional Eeveelutions knowing they could pull out which one they needed at the right time. It turned the little monster into a traveling toolbox.
Neo Destiny was the first time the Eeveelutions went out to play and conveniently forgot to invite their younger sibling to the party. They show up in this set with no sign of Eevee. Neo Destiny introduced Light Pokémon, which were the other side of the coin to Dark Pokémon. Here were creatures that were made of kindness, kisses, and collaboration. The standard Light Pokémon will heal allies, ward off attacks, etc. The artwork focuses on serenity, and even Flareon's flames look downright snuggly in this.
The most interesting of these cards is Light Jolteon and its Pulse Guard. Reminiscent of Mr. Mime's Invisible Wall, this attack means that your opponent can only peck away at Jolteon's health. Nowadays, with so many cards swinging in the hundreds of damage, it could act as an infinite stall. Stalling is only an effective strategy if you have something to build up to, and Light Jolteon isn't packing the power by itself. However, if you need a few extra turns to get all the right cards in place, it is an infuriating way to do so. Even on their best behavior, Jolteon still has a few sharp edges.
In WOTC's final set of the game, they came out with a starter deck based around the original Eevee trio. It was called Eeveelution, and I immediately dropped my hard-earned preteen dollars on it. Was it good? No. Like most Pokémon theme decks, it was borderline unplayable. But it came with all three of the vulpine elementals, and I'd probably buy it again today.
The Skyridge versions aren't anything to write home about. Again, Jolteon is the odd one out from the trio, rendered in rudimentary (but for the time, cutting edge) 3D graphics. Vaporeon is really the only one I would consider using in decks that weren't built off gimmicks, as energy control is always a nice way to screw over your opponent.
Power Keepers was a good set for English players. In Japan, the Star Eeveelutions were restricted to the Play Promotional cards, which meant people actually had to go to game stores and play the game to earn enough points to get them. Can you imagine such a time? In this plague-stricken society?
For the English fandom, the cards were included in the set, which meant you just had to be willing to drop money. (Much simpler for the anti-socialites who dread game stores.) None of the cards are especially powerful, but they are all Basic Pokémon. That means you can cut an easily offed Eevee out of the equation, and for Basic Pokémon, they are decent. Am I going to pay $700 for a Near Mint Vaporeon Star with mediocre attacks? No, but only because I have to pay rent. Otherwise, hell yeah. Look at it. It's purple.
The GX era of Pokémon brought not only more of the main trio, but also an Eevee that was determined to fight alongside the big boys. As far as GX Pokémon go, this Eevee was still pretty lightweight. However, the ability to heal all damage from it when you evolve means that it's okay if this Eevee takes a couple whacks before you're ready to power up. Consider the fact that Devolution Spray Z was in Standard at the same time as this, and you have the opportunity to start fresh with a different Eeveelution. It's again another way to turn the petite vulpes into a toolbox.
Each of the Eeveelutions has different niches. Jolteon GX is great if you are off to an early start, and want to be able to snipe your opponent's benched Pokémon before they get a chance to power up. Vaporeon GX plays favorites with Water Pokémon, and is excellent support from the Bench with its Hydrating Drops Ability. Flareon GX is more of a closer, meant to be deployed late in the game where its Power Burner GX might be able to end a match. It's interesting to see just how far the different Energy archetypes have come. The Eeveelutions essentially serve as a metric for how much they've diverged over time.
In the most recent set released, the fox friends are back at it again. Their main gimmick this time revolves around the use of Memory Capsule—when that tool is attached, it shuts down Abilities for rivals. It's limited in functionality, but I could see this as effective hate against specific deck archetypes.
So there you have it. The only constant about Eevee and its branching routes is that they change, constantly evolving into something else. It's exciting to think of where they might go in the future, and how the little fox might keep us on our toes!