This particular one is entirely distinct from the others, being part of the rare group of Shining Pokmon cards
I spent quite a while counting letters and going through hundreds and hundreds of cards, so theres a chance I may have missed some of the more obscure ones
With the loss of Radiant Greninja as well, Gardevoir ex is in critical condition
The other unique feature is that there is also a holofoil version of each of the 25 cards available, and these holofoils have a special confetti pattern, a pattern only used for special promotions such as this
There's arguments to be had both ways, but if you can't see any way you'd be able to pay the upkeep, then you shouldn't use the spell
Pauper started as a "home-grown" format on Magic Online that eventually attracted enough players that Wizards made a legality filter for it, and it grew and grew from there until now it's a legitimate paper tournament format