This is a seamless high quality sand dunes sea terrain which is tillable on both the y & x axes using the array modifier.
The images show what the terrain looks like when it is tiled and when it is not.

My own render using this terrain:

-What's included:

•Packed Blender file

•Two versions: harsh and smooth

•Two LODs (Level of details)

Note: For the best results, scale the included textures in your target application to reduce the size of individual sand grains. Or replace the included displacement and normal maps with a noise texture.

I can do an unlimited number of variations; hire me to that end.