One feature added in Doubutsu no Mori e+ is the ability to add villagers to a town by swiping their corresponding e-Reader cards; this includes not only villagers from Animal Crossing, but also 84 new villagers (some of whom would return in later games). A similar feature would later be implemented with villager amiibo cards in the Welcome amiibo update for Animal Crossing: New Leaf and in Animal Crossing: New Horizons.

However, unlike amiibo card villagers, the new villagers in Doubutsu no Mori e+ are not present in the game's code. Instead, it allocates a portion of its save data to e-Reader villagers and fills in this blank space using information encoded on the cards themselves, namely a villager's name, physical appearance, initial catchphrase, personality, favorite song, and house type. Over 20 years after the game's release, dataminers discovered that this mechanic permits players to import custom villagers through the e-Reader alone, provided the necessary data is properly formatted.