Example of a Band Blocking Leatherback Baloth, a green creature with a power and toughness of 4/5
The smallest envelope according to USPS rules that qualifies as a letter (for standard stamp usage) is 5" by 3.5" so anything around that size works perfectly to fit a top-loader
Through the years, the core rules behind the Pokemon TCG more or less stayed the same, but the introduction of various new categories of cards has shifted the moment-to-moment "gamefeel" time and again
The first is a triggered ability: "When this permanent enters, target player may search their library for a card named [name], reveal it, put it into their hand, then shuffle." Note that the target player searches their library (which may be affected by effects such as that of Stranglehold) and that the card they find is revealed, even though these words aren't included in the ability's reminder text
As reported by The Gamer, it seems like The One Ring was hidden inside a booster pack acquired by the right person to find it