A boomerang remixed from: https://www.printables.com/model/36796-boomerang
I have added a region with 100% infill close to the throwing arm to create a better weight distribution. This adds approximately 3g to that arm which is close to adding a small coin as recommended by the original creator. The region with 100% infill can be easily moved, re-scaled or duplicated to fine tune the performance of the boomerang.