For instance, in the semi-recent Japanese set, Terastral Festival, you could pull a full set of the rare Eevee evolution (or Eeveelution) cards that are very rare and worth quite a lot of money each
The third-most expensive trading card in the wild, wild west is this Backless Blastoise card, which has a pretty interesting reason behind its rarity
The harmonize cost is steep, but your own scaling creatures make it easier to cast from your graveyard
You set up a team of four with the Pokmon you catch, and then swap them around in a 6X6 grid to form groups of 3, 4 or 5, to damage the Pokmon of the current level
With enough mana you can poison someone for 4, and even protect it via regenerate
This combo allows you to recoup the two energy you burn with each use of Psydrive (one from your turn naturally and one Gardevoirs ability), essentially guaranteeing 150-damage attacks with no drawbacks