Check out a useful free toolkit.
Ricardo Viana shared a free custom procedural environment shading toolkit for Blender. The system features a number of customizable parameters letting you set up different scenarios.
- Sun direction
- Night with/without stars
- Sun and horizon colors
- Sun intensity and scale
- Floor height
Please note that it works with both Cycles and Eevee. Please note that in Cycles you need bigger sun sizes. A moon is not included.
You can learn more and get the pack here.