The Pokemon series has an extensive history of innovation and experimentation. In every new Generation, Nintendo and the various developers of Pokemon media franchises implement aspects meant to keep these pocket monsters relevant and interesting for each new generation of gamers. This sometimes involves them using peripheral devices in conjunction with existing consoles.
In 2003, Nintendo released an e-reader device that could attach to the Game Boy Advance to allow players to scan special cards to enhance gameplay and add cool features to certain games. Crystal Pokemon were a type of card created specifically for this peripheral, though they could also function as cards in physical decks. Since the Pokemon TCG's e-card series ended over a decade ago, Crystal Pokemon have become some of the rarest cards on the planet, though not all are equal. Some of these Crystal Pokemon are better to have in a battle than others due to their mightier moves.
9 Kingdra
All Crystal Pokemon have a couple of similarities. Firstly, they all have the Poke-Body ability known as Crystal Type, which changes their element for a turn depending on what kind of energy card gets attached to them. Another similarity is that all of their moves require more energy as well as a more diverse assortment to be used.
This makes playing a Crystal Pokemon quite a challenge and can hinder certain cards enough to be virtually ignored aside from the collection aspect of the TCG. Kingdra from the Aquapolis set is one such card. They are tied for the highest HP for all Crystal Pokemon, yet their costly and lackluster attacks make them virtually unusable.
8 Lugia
Legendary Pokemon are usually extremely powerful, though this is not always the case. Lugia, also from the Aquapolis expansion, proves this with its relatively low HP and mediocre attacks. Its Psychic can be useful against foes loaded with energy cards, though its Steam Blast attack can only realistically be used a couple of times before it becomes a burden to the trainer's energy needs.
The gimmick of being a Crystal Pokemon also works against Lugia's Colorless-typing, as its attacks now require much more diverse energy than normal cards.
7 Golem
Golem from the Skyridge set is a bit more useable, though not by much. Its Rock Throw is as generic as TCG attacks come, though at least its energy cost is not ridiculous. Golem's Earth Bomb attack, however, is a risky move to use as it is uniquely designed to injure friends as well as foes.
For the 50 damage it does to the opposing Active Pokemon, Golem does 20 to itself and 10 to every Benched Pokemon on both sides of the battlefield.
6 Celebi
Although one of the Crystal Pokemon with the lowest base HP, Celebi from the Skyridge set can be a decent support card. With the right timing and energy attachment, Celebi's Empathic Healing can restore some health in dire circumstances for itself and others who share the same type.
This is one aspect in which the Crystal Type Poke-Body ability can be used strategically. Celebi's Mind Bend can make an enemy Confused with a lucky coin flip, though at 20 damage per hit it may not be worth the effort.
5 Ho-oh
As another legendary with lower than average health, Ho-oh's usability is limited, though it can be run as a decent Basic Pokemon in some Fire and Water-type decks. Holy Flame does negligible damage, though Ho-oh's Scalding Steam may be worth using if one has spare energies to burn.
One aspect of this card that fans might find interesting is that its Crystal Types are Fire, Water, and Electric; the types of the Legendary Beasts Entei, Suicune, and Raikou which Ho-oh is often associated with.
4 Kabutops
Being the only one of fossil origin out of all the Crystal Pokemon, the Skyridge expansion's Kabutops holds a special niche for collectors, though it is quite functional in battle as well.
Draining Cut can be handy if one is lacking HP and wants to do a bit of damage at the same time. However, Triple Cutter is the main reason to use this card. With the potential to deal 90 damage, it is one of the better Crystal Pokemon attacks.
3 Nidoking
Nidoking from the Aquapolis set actually has two good attacks, both of which are useful in different situations that give this Stage 2 Pokemon some versatility. Nidoking's Poison Horn may be a bit high-cost, though making the adversary Poisoned will eventually pay off if the foe does not heal and remove this special condition.
Rolling Thunder is also pretty good in that it deals decent damage and has the potential to hit all of the opposing team's Benched Pokemon for 10 HP each while landing 50 damage on the Active enemy. However, there is a coin flip involved that can lead to the user's own Benched Pokemon taking the stray bolts of this attack, therefore this move should be used with a bit of caution.
2 Crobat
Here's another card with good versatility. Crobat from the Skyridge set has a hazardous attack called Poison Flame, which can put the opposing Active Pokemon in a tight spot as it can leave them Burned and Poisoned following a single coin flip.
This amounts to 30 damage every turn for very quick damage over time compared to similar moves from other Pokemon. Crobat's Squared Attack should not be ignored either, as it can do a maximum of 80 damage to an adversary with some good fortune.
1 Charizard
As fans of the TCG are likely well aware, there is strong favoritism shown toward Charizard cards in many different expansions. The Skyridge set is no exception, as it was released with another mighty flame Pokemon to add to the ranks of Charizard cards across the franchise.
While Fireblast is a decent attack, it also requires discarding an energy card; consequently, it is preferable to use this Fire-type's other move: Dragon Tail. This draconic devastation can deal 100 damage per hit, given good coin flips. This is the highest maximum damage any Crystal Pokemon can unleash. Combined with Charizard's high HP, this makes it the best out of all the crystalline variants.