FindAssetsOfTypeInProject.cs

public class Helper
{
	public static List<T> FindAssetsByType<T>() where T : UnityEngine.Object
	{
		List<T> assets = new List<T>();
		string[] guids = AssetDatabase.FindAssets(string.Format("t:{0}", typeof(T)));
     
		for( int i = 0; i < guids.Length; i++ )
		{
			string assetPath = AssetDatabase.GUIDToAssetPath( guids[i] );
			T asset = AssetDatabase.LoadAssetAtPath<T>( assetPath );
			if( asset != null )
			{
				assets.Add(asset);
			}
		} 
		return assets;
 	}
 }