Looper
Looper is a sketch plugin that helps automate duplication of groups and layers. One can control properties like Rotate, Scale and Opacity while duplicating. This powerful combination enables artists and designers to create interesting geometric and organic patterns.
Looper website | Download | Github

Screen recording of Looper generating patterns in Sketch App

Screen recording showcasing live tweaking of parameters

Sample patterns generated using Looper

Sample starting shapes and final patterns generated using Looper
Stats
Monthly active (MAU): ~28,812
Overall usage since launch (Apr 8, 2017 – Apr 8, 2018): 434,973