Story, first published: Science Fiction Stories, Sep. 1956
A reporter, investigating an "epidemic" of good luck stories, finds the cause to be alien Brownies performing acts of love and kindness, neighborliness, and brotherhood. (When the Brownies tried to contact us in the past, they became the subjects of folk tales and superstitions.)
Ewald, Robert J.: When the Fires Burn High and the Wind is from the North, p.53
Nicely told story about the correspondent who begins to believe in "brownies" and "fairies", and discovers them all over the place. Shimmers with wonder and feel-good emotions.