I know lots of folks are new to CNC here or new to design software. Langmuir’s new file sharing option is great (a couple of thousand! designs already) but I figured I’d post this link just in case folks are looking for more.
I often start a new design with an existing design to cut down the design work (and still end up spending an inordinate amount of time in design 
) and the link has some good sites for free DXF designs.
It’s a bit dated and there are even more sites out there but for folks looking for a start.