These look very simplistic but effective and would look great in-built to a operating system. A resized smaller version that displays on file lists so to make the file extension actually look good with these brilliant icons. A good choice of colours. None of the colours are too harsh on the eyes; they’re all soft. Also, the rounded edges just contribute to the whole feeling of them been soft and nice on the eyes. In conclusion, an awesome icon set for anyone developing an operating system with a modern theme.