-arduino IDE -write and upload arduino code- https://github.com/arduino/Arduino/tree/1.6.8
-OpenSCAD -write and visualize 3D modeling- http://files.openscad.org/
-slic3r -slice 3d models to gcode for printing- http://slic3r.org/download

These 3 for situations where I am travelling and do not have a full size laptop, none are properly available for Android but can be accessed over a bluetooth VNC using my tablet and it's keyboard cover as a terminal to access the N900 apps.