If they can take Colorless, they too can be powered up by Dialgias Metallic Turbo
The key tweak is the shift in how energy works: rather than filling your deck with specific energy cards, you simply select the type (or types) of a deck when building it, and energy is automatically generated once per turn for you to attach how you wish (for two-type decks, which are required for the Dragon Pokmon lines such as Dragonites, which type comes up next is randomised, which effectively replicates a multi-type deck equivalent in real life)
Big G is a fantastic, iconic black card, and one thats certainly worth the price of a pack
Each pack contains 3 different cards: 2 of them are individually guaranteed to be Normal (aka Common) or Rare, while the third card is guaranteed to be Rare, Super Rare, or Ultra Rare
But they exist anyway, like postcards from an alternate Pokmon universe where everything is just bigger for no reason