Perlin noise is commonly used to create natural looking textures in computer graphics. A common example is it's use to create a randomly generated landscape, or realistic looking clouds.
Ken Perlin invented the Perlin noise algorithm following CGI work on the movie Tron.
siv::PerlinNoise is a good header-only Perlin noise library for C++.
The Python library noise has Perlin “improved” noise and Perlin simplex noise algorithms.