nitroplasm
nitroplasm is a simple wallpaper setter for the Plasma desktop intented for use with the custom root menu by MatMoul. It is named as a nod to nitrogen, the best standalone desktop wallpaper setter which is my inspiration for this project.
The program is currently very simple -- it displays a fixed size window with controls along the bottom which allow you to bring up a file chooser to select the image you want to use, choose the way you want to apply it, choose which monitor to apply it to, and to actually apply it as the desktop wallpaper. When you select an image, it will show in the blank space in the middle of the window.
I created this program since I don't know of any way to launch the vanilla Plasma desktop settings configuration applet by the command line (If you know, tell me! I feel really weird not knowing!), and if you disable the default context menu for the Plasma Desktop, you lose all access to the desktop wallpaper setting (unless you manually edit the plasma config file and restart plasmashell).
The dependencies are only pyQt5, pydbus, and plasmashell. If you want to set a different wallpaper for each monitor, you need xrandr installed as well. I have issues open to improve nitroplasm and make it more like nitrogen, but we'll see if time allows. It's at least usable for now.