The Pokémon TCG: EX Hidden Legends expansion was released on June 14th, 2004.

EX Hidden Legends

EX Hidden Legends adds an incredible amount of new strategy to the Pokémon TCG. Many of the Pokémon have never-before-seen attacks that change the way you play. There are more ways to get cards into and out of your hand. New Stadiums alter a match's rules and add more fluidity to a battle. New Ancient Technical Machines add an element of surprise to any player's tactics. Are you ready to discover all of the hidden legends?

Give Yourself a Hand!
EX Hidden Legends provides even more ways to get useful cards into your hand. Whether it's by drawing lots of cards or searching your deck for specific cards, you'll be able to use your strategies faster!

As long as you have seven or less cards in your hand, Steven's Advice (92/101) allows you to draw a number of cards equal to the number of your opponent's Pokémon in play. That means that, unlike TV Reporter or Delcatty's Energy Draw, you can draw up to six cards without having to discard any of them!

Corsola (32/101) is similar to Steven's Advice. Its Coral Glow lets you draw a number of cards up to the number of your opponent's Basic Pokémon in play. Corsola also has an attack that does 40 damage, so it's not limited to card drawing.

Igglybuff (37/101) makes its first appearance in the EX series and instantly makes itself useful. Igglybuff's Set Song lets you search your deck for a Basic Pokémon and a basic Energy card and put them into your hand. With the large number of strong Basic Pokémon in EX Hidden Legends, you can put together a good team quickly and ensure they have enough Energy to act!

Life is Precious
Some exotic new healing methods are now available in EX Hidden Legends. One of the more powerful new ways, the Life Herb (90/101) is a new Trainer that can cure any Special Condition and remove an amazing six damage counters from a Pokémon! Unfortunately, it doesn't work on Pokémon-ex or Pokémon with an owner's name, and it only works with a successful coin flip. It's not a Supporter, though, so you can again if you have another Life Herb in your hand. Bellossom 's (16/101) Heal Dance is less powerful, but it is a more reliable way to heal your Pokémon. Heal Dance is a Poké-Power that lets you remove two damage counters from any Pokémon. It's like having a Potion card every turn!

If you require healing for your entire team, a Milotic (12/101) could be just what you need, but be careful about how you use it. When played from your hand, Milotic heals ALL of the damage counters from every Pokémon in play that is not a Pokémon-ex, whether they are yours or your opponent's! If you don't want to heal your opponent's Pokémon, make sure you evolve a Feebas with a card from the deck, like with Wally's Training or Feebas' own Ascension ability. Since Milotic comes from the deck instead of your hand, the Poké-Power doesn't take effect.

Finally, there's Tropius (27/101). Tropius provides healing and Energy simultaneously with its Fruition ability. Fruition moves an Energy card attached to Tropius to another Pokémon and remove four damage counters from that Pokémon. That means that you can pay the Retreat Cost for an injured Pokémon, make Tropius active, and then use Fruition to put Energy back onto the retreated Pokémon. Or, you could use Gardevoir's Psy Shadow to attach a Psychic Energy to a Pokémon, then use Fruition to move another Energy card to that Pokémon and remove the two damage counters. Or, how about using Tropius with Regirock ex or Ludicolo to heal it faster? In 2-on-2 Battle, Tropius works great with a Pokémon like Slaking or Sceptile ex. Since Slaking and Sceptile ex can only attack with their 100-damage attacks every other turn, you can use Tropius to heal them between attacks. There are plenty of other uses for Tropius... can you find more?

Source: https://www.pokemon.com/us/pokemon-tcg/ex-hidden-legends