The phrase "signature motifs" refers to specific elements or patterns that are distinct and unique to someone or something. It is similar to a personal or recognizable style that sets them apart from others. Full definition
The color black and the letter X became signature motifs. (en.wikipedia.org)
For her second exhibition at the gallery, from morning, Yuko Murata's paintings continue the artist's distinctive signature motifs of animals and landscapes. (jamescohan.com)
Fans of Japanese contemporary artist Yayoi Kusama need no introduction to the Kusama pumpkin - her dotted signature motif and yes, alter ego. (hifructose.com)