Before Pokémon launched in the US, Trainer Deck A (aka Brock's Deck) was quietly distributed to help League Leaders get familiar with the TCG.
These decks weren't sold to the public — all cards were marked with red borders and lettering on the back to help prevent resale. But of course, that only made them more coveted over time...
Since I work at Courtyard.io and nerd out about these kinds of stories, I was hyped to see this Onix from the deck in land in our Pokémon auction this week.