A simple and naive C# program that will help identify binary file types in a directory.

FindBinaryFiles.cs

/*
 * Recommended usage is to pipe in a list of paths :
 *  Git: 
 *      git ls-files | FindBinaryFiles.exe
 *  PowerShell: 
 *      ls -r | ? PSIsContainer | select -expand FullName | FindBinaryFiles.exe
 * */

using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Text.RegularExpressions;

class Program
{
    static void Main()
    {
        var files = GetFileListFromStdin()
            .Select(f => f.ToUpperInvariant())
            .Where(NotExcluded)
            .GroupBy(Path.GetExtension)
            .OrderBy(g => g.Key)
            .Where(g => g.Key.Length != 0);
        Console.WriteLine("Binary files:");
        foreach (var extn in files)
        {
            if (extn.Any(IsBinaryFile))
            {
                Console.WriteLine(extn.Key);
            }
        }
    }

    static IEnumerable<string> GetFileListFromStdin()
    {
        string s;
        while ((s = Console.ReadLine()) != null)
        {
            yield return s;
        }
    }

    static bool NotExcluded(string fullPath)
    {
        var exclude = new[] { @"\\ThirdParty\\", @"\\bower_components\\", @"\\node_modules\\" };
        return !exclude.Any(ex => Regex.IsMatch(fullPath, ex, RegexOptions.IgnoreCase));
    }

    static bool IsBinaryFile(string fullPath)
    {
        using (var file = new FileStream(fullPath, FileMode.Open, FileAccess.Read, FileShare.Read, 10240, FileOptions.SequentialScan))
        {
            while (true)
            {
                int currentByte = file.ReadByte();
                if (currentByte == -1)
                    return false;
                if (currentByte == 0)
                    return true;
            }
        }
    }
}