They're meant to be easy on-ramps to EDH, but the new cards, ease of use, and powerful reprints make them favorites for even veteran players
This makes it one-sided, and the fact it minuses stats as opposed to doing damage means it gets around indestructible effects as well
Any ability that provides double strike to a creature is handy
Look for spikes in popularity: New Pokmon movie, series or game
These are: Traveling Chocobo (Black) - Borderless, Japanese exclusive: cheapest listing for $7,500 on TCGPlayer, $12,120 average listing Cloud, Midgar Mercenary - Pro Tour Promo: cheapest listing for $800 on TCGPlayer, $3,775 average listing MTG's Most Expensive Modern Cards Explained Although they are both very rare, these are not "unique" cards, in the sense that multiple copies were printed very recently, and they are in someone's possession
These Japanese promotional Pokmon or Pocket Monster cards have a double star which points to rarity too