This is my tribute/homage to an old free design called the 'Anycopter' that Flite Test released back in ~2013. Using two of the circular plates (Everycopter_hub) & the correct number of square hardwood booms, you can build a tricopter, quadcopter, pentacopter, hexacopter, octocopter, Y4, Y6, X8, etc. The additional rectangular plate (Everycopter_top_plate) can be used either on the top, or on the bottom, or both, for mounting batteries &/or payloads - slots are provided for battery straps & the central holes are designed to accommodate a 1/4" UNC (tripod) bolt. Additional circular plates can be stacked above/beneath to provide more covered space for electronics.
The included .DXF files are the exact files that I sent to a carbon fibre CNC factory in Shenzhen to have cut in 2mm carbon fibre. There are lots of places in China that will happily cut small batches (even just one or two parts) of carbon fibre parts & post them to you for very reasonable prices, if you aren't lucky enough to have local access to CNC equipment/services.
The Everycopter_15mm_* files are jigs that can be 3D printed to help with preparation of 15mm hardwood booms (to drill mounting holes & cut angles). The width of these is actually 15.15mm which is a nice snug fit with my printer & the hardwood booms I used, but YMMV.