Import textures as truecolor rather than compressed by default

I had this question too. Although you don't have a configuration panel for that, you can override the default Import Settings with an Editor script. I found a similar solution and created this script:

 using UnityEngine;
 using UnityEditor;
  
 public class TexturePreProcessor : AssetPostprocessor
 {
     void OnPreprocessTexture()
     {
         TextureImporter importer = assetImporter as TextureImporter;
         Object asset = AssetDatabase.LoadAssetAtPath(importer.assetPath, typeof(Texture2D));
         if (!asset)
         {
             importer.textureType = TextureImporterType.Advanced;
             importer.npotScale = TextureImporterNPOTScale.None;
             importer.mipmapEnabled = false;
             importer.textureFormat = TextureImporterFormat.AutomaticTruecolor;
         }         
     }
 }

Note that when you import new textures it will change the default settings to Advanced / No power of 2 scale / no mipmaps / automatic truecolor. You can still manually change the Settings to another after you've imported a texture.

If all your textures must be in an exact Setting, you could remove the is it already an asset test to make it a little faster.