While Shaymin mitigates this issue slightly, some decks need other cards to protect themselves if Shaymin is knocked out, and Charmeleon is a card that is self-sufficient in this regard
When the Pokemon this card is attached to is damaged by an opponent's Pokemon's attack, put 6 damage counters on the attacking Pokemon
Ixhel comes built-in with an alternate win condition, allowing you to poison out an opponent with its toxic 2 ability, and once a player hits ten poison counters, they're automatically out of the game, making it, so you only have to connect with a player five times to completely poison them out
Mid-battle is a great time to switch Mewtwo ex into the Active Pokmon spot to attack with its Psychic Sphere move for 50 Psychic damage
Not all build around cards are created equal, though, and Lasting Tarfire from Lorwyn Eclipsed is a real dumpster fire of a card
Tutor and recursion effects are more powerful in singleton formats giving this guy another boost in power