I was thinking along the lines of a walking fire-starter or perhaps a grapple-belt that had a retractable rope or cord that would make climbing easier.
Or perhaps a walking incendiary device?
Or a taser-fork that only does non-lethal damage.
The possibilities are endless!
It's been a long time since I last played D&D, and even then I hadn't played it for many sessions. But one thing piqued my interest in the 5th edition Player Handbook...
GNOME TINKERING!
I'm always a Gnome Rogue when I play, and the little clockwork toys I could potentially make are...