Akcja and other 85,000 icons from Icons8 icon pack follow the visual guidelines of the operating systems: Windows, iOS, Android KitKat, and Material. PNG format is free up to 100x100 px. Icons are availble for download in PNG and vector (SVG, PDF, EPS, and more).
It is a clenched fist with the thumb crossed over the folded in fingers. The fist is being held up in the air, and there is a line drawn above the knuckles of the fist that has a peak over the index, middle, and little fingers.