To run graphical X-programs remotely you first need a PC with an X Window system. I use my Laptop with a Debian Stretch installation and a Xfce Desktop.
On Wikipedia - X Window System you will find:
Unlike most earlier display protocols, X was specifically designed to be used over network connections rather than on an integral or attached display device. X features network transparency, which means an X program running on a computer somewhere on a network (such as the Internet) can display its user interface on an X server running on some other computer on the network. The X server is typically the provider of graphics resources and keyboard/mouse events to X clients, meaning that the X server is usually running on the computer in front of a human user, while the X client applications run anywhere on the network and communicate with the user's computer to request the rendering of graphics content and receive events from input devices including keyboards and mice. The fact that the term "server" is applied to the software in front of the user is often surprising to users accustomed to their programs being clients to services on remote computers.
So first the X server should be able to display local X programs (X clients) like a graphical desktop, firefox and any other local graphical programs. That's usually the case. Now it is only one little step to get the display of remote running X programs (X clients).
On my RasPi with Raspbian Stretch Lite without any graphical user interface I installed some small X test programs:
rpi ~$ sudo apt install x11-apps
Some of this nice little programs are xeyes or xclock. On my Laptop I can now start:
laptop ~$ ssh -X firstname.lastname@example.org xeyes
and see the eyes following the cursor on the laptop. If you start xclock you will see the time on the RasPi. It's now up to you to install the X programs you need. For example a file manager would be nice to manage the files on the RasPi from your Laptop. The default file manager of Xfce is thunar. A generic lightweight X11 file manager is Xfe. But this programs will install many more additional libraries than the simple x11-apps.