First there is the placement of "Urza's Saga (Argoth)" in 65
Metagross ex - Ability: X-Boot - during your turn, you may look in your deck for a Basic Psychic Energy sv3pt5 207, a Basic Metal Energy SFA 99, or one of each and attach them to your Pokmon, Psychic or Metal
The mechanic was introduced in 1996s Mirage block, which told the story of the planeswalker Teferi Akosa and how his experiments with time manipulation affected the continent of Jamuura
Holo (Holographic): The artwork of the Pokmon is shiny
Notably, if it has somehow gained double strike, it will convert before dealing combat damage in the regular combat damage step
It restricts you to the top card of your library, but that card will almost always be playable later in the game when you have plenty of mana to spend