Generic MonoBehaviour inspector for Unity that adds type-specific color-coding to the inspector header for visual distinction. Doesn't work when inspectors are collapsed though. ):

EditorLayoutUtil.cs

using UnityEngine;

namespace Code.Editor.Utilities
{
  public static class EditorLayoutUtil
  {
    public enum RectDirection
    {
      Horizontal,
      Vertical
    }
    
    public static (Rect leftTop, Rect rightBottom) Split( this Rect position, float size, RectDirection direction=RectDirection.Horizontal )
    {
      if(direction == RectDirection.Horizontal)
      {
        return (
          new Rect( position.x, position.y, size, position.height ),
          new Rect( position.x + size, position.y, position.width-size, position.height )
        );
      }
      else
      {
        return (
          new Rect( position.x, position.y, position.width, size ),
          new Rect( position.x, position.y + size, position.width, position.height - size )
        );
      }
    }
  }
}

MonoBehaviourInspector.cs

using System;
using System.Collections.Generic;
using Code.Editor.Utilities;
using UnityEditor;
using UnityEngine;

namespace Code.Editor.Editors
{
  [CustomEditor(typeof(MonoBehaviour), true, isFallback = true)]
  public class MonoBehaviourInspector : UnityEditor.Editor
  {
    private static float PickerWidth => 2f * EditorGUIUtility.singleLineHeight;

    private static readonly Dictionary<string, Color> colorCache = new Dictionary<string, Color>();

    public override void OnInspectorGUI()
    {
      var type = target.GetType();
      var inspectorStyle = (GUIStyle) "IN Title";
      var width = EditorStyles.inspectorDefaultMargins.fixedWidth;
      var mockContent = new GUIContent( type.Name, AssetPreview.GetMiniTypeThumbnail( type ) );
      var height = inspectorStyle.CalcHeight( mockContent, width ) 
                   + inspectorStyle.margin.vertical 
                   + inspectorStyle.padding.vertical;
      var topPadding = EditorStyles.inspectorDefaultMargins.padding.top;
      var colorPos =  EditorGUILayout.GetControlRect( true, height, GUILayout.ExpandWidth( true ) );
      // HAHAHA We can GIVE THE RECT BACK??? XDXDXD
      EditorGUILayout.GetControlRect( true, -height-topPadding, GUILayout.ExpandWidth( true ) );
      colorPos.y -= colorPos.height + topPadding;

      var pickerPos = EditorGUILayout.GetControlRect( true, EditorGUIUtility.singleLineHeight, GUILayout.ExpandWidth( true ) );
      EditorGUILayout.GetControlRect( true, -EditorGUIUtility.singleLineHeight-topPadding, GUILayout.ExpandWidth( true ) );
      ( pickerPos, _ ) = pickerPos.Split( EditorGUIUtility.labelWidth );
      ( _, pickerPos ) = pickerPos.Split( pickerPos.width - PickerWidth );
      DrawColoredBackground( colorPos, pickerPos, type );
      
      base.OnInspectorGUI();
    }

    private static Color getColor( string key )
    {
      if( colorCache.TryGetValue( key, out var cached ) )
      {
        return cached;
      }
      
      var currentColor = EditorPrefs.GetString( key, "" );
      if( !string.IsNullOrEmpty( currentColor ) )
      {
        var components = currentColor.Split( ',' );
        if( components.Length == 4
            && float.TryParse( components[0], out var r )
            && float.TryParse( components[1], out var g )
            && float.TryParse( components[2], out var b )
            && float.TryParse( components[3], out var a ) )
        {
          colorCache[key] = new Color( r, g, b, a );
          return colorCache[key];
        }
      }

      colorCache[key] = Color.clear;
      return colorCache[key];
    }

    public static void DrawColoredBackground( Rect position, Rect pickerPosition, Type type )
    {
      var prefKey = $"ComponentColor_{type.Name}";
      var color = getColor( prefKey );
      
      var prevColor = GUI.color;

      GUI.color = color;
      GUI.Box( position, GUIContent.none, WhiteTextureStyle );

      GUI.color = prevColor;
      
      EditorGUI.BeginChangeCheck();
      var newColor = EditorGUI.ColorField( pickerPosition, color );
      if( EditorGUI.EndChangeCheck() )
      {
        saveColor( prefKey, newColor );
      }
    }

    private static void saveColor( string key, Color color )
    {
      colorCache[key] = color;
      EditorPrefs.SetString( key, $"{color.r:f2},{color.g:f2},{color.b:f2},{color.a:f2}" );
    }
    
    private static GUIStyle whiteTextureStyle;
    private static GUIStyle WhiteTextureStyle
    {
      get
      {
        if (whiteTextureStyle != null)
          return whiteTextureStyle;
        whiteTextureStyle = new GUIStyle
        {
          normal = {background = EditorGUIUtility.whiteTexture}
        };
        return whiteTextureStyle;
      }
    }
  }
}