FLV and other 86,400 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).
The icon looks like it is a plain page of paper with a dog eared corner. Placed on the paper are the capital letters "FLV." One would normally think this icon associates with some sort of computer file.