Copying a value creature draws you a pile of cards, while copying a powerful threat like a Titan or a big ETB effect like Agent of Treachery can straight-up end the game
In addition to their Energy requirements, Crystal Pokmon also stand out because of the Pok-Body (a precursor to modern Abilities) which they all share : Crystal Type
When your Mega Evolution Pokmon-ex has been Knocked Out, your opponent takes 3 Prize cards
Confusing sentimental value with market value -- Your Base Set Pikachu is not necessarily rare
Shivan Hellkite is a tough cut, as well, since if we ever untap with it, we almost surely win
In fact, do keep in mind how these cards are made, because Ill be showing you how this method of card designing has been pretty much the same since the beginning