I have always had a thing for sprues, the plastic frames used in the injection molding process and to hold model parts in place. Anyone who does any scale modeling or tabletop game modeling likely has tons of this stuff lying around (if you don't throw it all away). I'm always looking for new ideas of how to re-use sprues.
Jon at Miniature Hobbyist is seriously sprue-obsessed. He not only has dozens of ideas for how to re-purpose sprues, he even breaks them down in acetone and creates what he calls "Oooey-Gooey Spruey." He uses this liquefied plastic material as gap-filler, to extrude tubing and hosing, and as a casting medium.
In this video, Jon creates an Ork Tie Fighter entirely out of sprue.
Here's a piece I did on Adafruit about his 4-part video series with nearly 40 different sprue-use ideas.