Curl Noise[1] is also cool. I've used it to create some gas giant planets for video games [2] though I used opensimplex noise [3] rather than perlin as the base noise, but either will work.

[1] https://www.cs.ubc.ca/~rbridson/docs/bridson-siggraph2007-cu... [2] https://github.com/smcameron/gaseous-giganticus [3] https://en.wikipedia.org/wiki/OpenSimplex_noise