This is a paid asset, but now you can download Farland Skies – Low Poly for FREE, but please remember this package is provided only for learning purposes or to be able to test before buying the product, NOT FOR COMMERCIAL PURPOSES.
Detail this asset from Unity Store: Original Link
Farland Skies – Low Poly v2.5.2
Minimalistic, low-poly style skybox with a custom single-pass shader that works as a regular skybox material, avoiding the use of any sphere or mesh.
Customization Demo
Day-Night Cycle Demo
Features:
• Dynamic three-color gradient sky with adjustable exponents.
• Three types of stars, with adjustable twinkling speed and horizon extinction.
• Five types of sun and moon, with customizable size, tint, and position.
• Three types of nifty low-poly clouds with dynamic height and tint.
• Fully customizable day-night cycle.
• Easy to control either from scripts or directly in the editor.
• High Performance. Optimized for mobile devices and VR platforms.
• Supports both Built-In and Universal Rendering Pipeline.
Also, it’s easy to integrate, just drag prefab to your scene and you’re ready to go!