Run this PHP script via command line and see all the directories with contents over 1 KB.

scanDir.php

<?php
// Base directory is where you run the script from
$currentDirectory  = '.';

// Get all contents, minus pointers to . and ..
$baseLevelContents = array_diff( scandir( $currentDirectory ), array('..','.') );

// All directories
$baseDirs = array_filter( $baseLevelContents, "is_dir" );

// All base files
$baseFiles = array_diff( $baseLevelContents, $baseDirs );


// Iterate through the all the directories
foreach( $baseDirs as $dir ) {
    
    // Recursively get the total file sizes
    $totalFileSize = getFileSizeSum( $dir );
    
    // If exceeds limit, do something
    if( $totalFileSize/1024 > 1  ) {
        echo $dir."/ seems to contain ".number_format($totalFileSize/1024)." KB of data.";
    }
}

// Method that returns the sum of all file sizes
function getFileSizeSum( $dir ) {
    $sum      = 0;
    
    // Get all contents, minus pointers to . and ..
    $contents = array_diff( scandir( $dir ), array('..','.') );
    
    // All directories
    $dirs     = array_filter( $contents, "is_dir" );
    
    // All base files
    $files    = array_diff( $contents, $dirs );
    
    // Sum all the files
    foreach( $files as $file ) {
        $sum += filesize( $dir."/".$file );
    }
    
    // Recusively call all sub directories
    foreach( $dirs as $subDir ) {
        $sum += getFileSizeSum( $dir."/".$subDir );
    }
    
    // Return the sum
    return $sum;
}