It is known that Windows provides the function to create a Windows Recovery tool, but it only contains a set of Windows Recovery Environment tools as mentioned before. And you are unable to add any custom tools in it. On the other hand, there almost no Windows PE tools support adding any custom tools or even it support, it may also be very complex to do so. Consider this situation, AOMEI PE Builder provides the "add custom tools" feature, you can use it to add the portable tools you want.
Please take a look at the picture below, in the lower left corner, you will find the "Add Files" button. This option is used to add the portable tools to Windows PE. As you know, portable tools are usually a single exe file or a folder with necessary files.
After click "Add Files", please refer to the following screenshot to add files or folders and read the note information.