Leafeon GX (Ultra Prism)

Leafeon GX is very tough Pokemon and is very hard to knocked out by Opponent's Pokemon because of its Ability Breath of the Leaves. This Ability allows you to heal 50 Damage from 1 of your Pokemon in play that has Leaf Energy Card attached to it. Also, take notes that Leafeon GX must be an Active Pokemon in order to use that Ability.

Evolving

An Eevee with the Ability Energy Evolution is the perfect for evolving Leafeon GX in fastest way. All you have to do is just attach an Leaf Energy card to Eevee and this Ability allow you to search Leafeon GX from your Deck and put it on Eevee.

Recovering 

Life Forest is a Prsim Star Stadium Card which mean you can only have 1 Life Forest Card in your Deck. This card has very powerful Healing Ability that allows you to remove 60 Damage and Special Conditions from 1 of your Grass Type Pokemon during your each turn. If you use together with Leafeon GX's Ability, you can remove up to 110 Damage Counters each turn.

In addition, this Stadium Card can't be remove from the effects of either Item Card or Supporter Card.

Cherrim's Ability Fair Weather Heal is similar to Leafeon GX Ability but its heal less Damage which 20 from 1 of your Pokemon that has Grass Energy Card attached to it. The great thing about Cherrim's Ability that this Pokemon doesn't need to be an Active Pokemon to use this Ability. In other words, you can heal other Pokemon while it is on Bench. Also, if your have more Cherrim in play, you can remove more damage

Using Gardenia  Supporter Card will heal 80 Damage from 1 of the Pokemon that has Grass Energy Card Attached to it.

Using Pokemon Center Lady will heal 60 Damage and remove all Special Conditions from 1 of your Pokemon

If you are in Situation where your Leafeon GX has Damage Counters that is beyond recoverable, you can use Acerola Supporter Cards to put Lefeon GX and all cards attached to it in your Hand and replace with another Leafeon GX.

If your attach Float Stone to Leafeon GX, its Retreat Cost become 0.  That means you can replace with another Leafeon GX without discarding any Energy.

Moreover, you can also use  Leafeon GX Ability 2 Times by retreating. The first time from an Old Active Leafeon GX and the second time from and New Active Leafeon GX. This way you can recover 100 Damage.