Lighting Box 2
https://assetstore.unity.com/packages/tools/utilities/lighting-box-2-hd-render-pipeline-integration-93057
low poly terrain
https://assetstore.unity.com/packages/tools/terrain/low-poly-terrain-46528
Low Poly Water GPU 
https://assetstore.unity.com/packages/vfx/shaders/substances/low-poly-water-gpu-79255
ALL SKY 
https://assetstore.unity.com/packages/2d/textures-materials/sky/allsky-10109?aid=1100l355n&gclid=CjwKCAjw2_LcBRBYEiwA_XVBUx2gsIqOdXhKQ0fFERfEVEpHEP28eoYFSsV7jZf1Tj3zd25kTBiZyxoC8iEQAvD_BwE&utm_source=aff