@pokemonrevolution recently presented a new and likely theory for these Grey Thick stamps, which I will quote here: Grey Stamp Theory Grey stamped 1st Edition Base set cards for the most part have commonly been considered to exist because of either A) The ink was low when they were stamped B) The stamp was not pressed down with enough force to create a nice dark color
Maralen of the Moonsong Maralen of the Mornsong may be jank, but its top level jank that wins if opponents dont know whats going on
Neutral power cards like Ash Blossom & Joyous Spring, Infinite Impermanence, and Pot of Extravagance slot into most decks
If it is less than five, this is a weak card
Earthen Ally Back when allies last had a real moment in Standard, the strategy revolved around going wide and scaling small creatures into real threats
Unsurprisingly, the card has never been particularly expensive because of this, often selling for around $1.80 on average