Frequency spectra of eight stars with additional signals of unknown origin forming a period ratio of around 0.47–0.49. The horizontal axis is scaled with a first-overtone frequency. Red boxes indicate the position of signals forming a period ratio in the range of 0.467–0.488. In the upper-left corner of each panel, we provide the star’s EPIC number, and in the upper-right corner, we provide the classification. If no classification is given, only the unknown signals were detected.