Layer Modes, sometimes called Blending Modes, allow you to combine layers in a variety of ways. We'll begin with the Normal modes and work our way through many, but not all, of the Layer Modes available on the latest (at the time I write this) version of GIMP, 2.10.20.

Links:

https://fontlibrary.org/

https://www.ahuka.com/gimp/free-public-domain-and-cc-assets/

https://fontlibrary.org/en/font/fivefoldornamentsetc

https://www.youtube.com/watch?v=17Iivi0tmug

https://www.gimp-forum.net/Forum-GIMP

https://www.ahuka.com/gimp/normal-layer-modes-erase-merge-and-split/