Others have spotted Celadon City in the background of Spearow’s card, Kanto’s Route 11 in Diglett’s card, Lavender Town in Haunter’s card, Kanto’s Route 17 in Dodrio’s card ...

It isn't all bad, though, as Haunter is one of these Pokemon that evolved via a trade. Generation One of Pokemon also had the unfortunate balancing issue of the Psychic type being overpowered.