Knotter : Make Celtic knots and custom interlaces 2015-12-22

Knotter is a free and open source customizable interlace designer made by Mattia Basaglia

F-Engrave : converts TTF and other fonts/files to G-code: Converts TTF and other fonts, as well as DXF and bitmap images to G-code for engraving
DMAP2GCode : Convert greyscale images to G-code: Tool to convert grey scale images to depth of cut G-code - no thrills, just conversion
G-code Ripper : scales, rotates, splits and wraps G-code: Transform a G-code job without returning to the CAD file. Now with "auto probe" for uneven surfaces
How to recycle HDPE (bottles, caps, etc.) into sheets / blocks to CNC: Some very good Instructables / YouTube showing how to easily recycle HDPE and work with the material
Convert photos to pencil sketches, drawings or even paintings: Looking to convert photos to sketches to etch, burn or engrave ? These two tools will do the trick.