I like to make @m_raynsford’s Escher fish that were in a similar thread a while back. I made a version of the SVG with just a single fish that can fit in some pretty small scraps.
I also have my own version of the infamous “round tuit” that I cut to use up scrap:
If I have enough room to cut the full square, I engrave the “TUIT”, score the decoration, and cut the square, then flip it over to the other side and repeat the engrave and score on the other side (along with a final cut on the circle). That allows me to keep the front and back TUIT aligned. If I’m particularly tight on space, I just cut the circle and do my best to align it for the back side engrave.