It's FOSS - https://itsfoss.com/best-gnome-extensions/
Brief: You can enhance the capacity of your GNOME desktop with extensions. Here, we list the best GNOME extensions to save you the trouble of finding them on your own.
GNOME extensions are a major part of the GNOME experience. These extensions add a lot of value to the ecosystem whether it is to mold the Gnome Desktop Environment (DE) to your workflow, to add more functionality than there is by default, or just simply to freshen up the experience.