This one is a drawing application I made in Unity, maybe 2 or 3 years ago, as I was learning about compute shaders. I actually still use it sometimes to draw silly pictures and annoy my friends on discord. It's named SnoopBoard, just because I was using a Snoop Dogg picture to test some of the features, so it ended up having that name.
It has some very basic features, such as:
Drawing (of course)
Straight vertical and horizontal lines
Variable roughness of the blackboard surface
Undo, redo, save & autosave/load of the last picture drawn
Very basic edge detection filter
There aren't really many reasons to use it over an actual drawing software, but it was an overall educational and fun project.