Allemansrätten, the right of public access, is one of Swedens unique “features.” It gives anyone access right to private property, with a few exceptions (homes and private gardens). The allemansrätt also gives you the right to harvest wild fruits, berries, and herbs. Lingonberries, blueberries, raspberries, blackberries, and mushrooms are some of the delicacies you can gather for free.
The Local has an article about foraging in Sweden. Read it.
In addition to what you can find in the forests, you can also find domestic fruits and berries that you can pick in both rural and urban areas. You are free to pick them on public properties and when you find them in abandoned unfenced gardens. Apples, cherries, raspberries, and pears are quite common.
Many communities plant fruit trees and berry bushes on public properties for anyone to enjoy. Make sure to treat these areas with respect and not disturb animals, plants, and humans when you hunt for the treasures of Swedish nature.