We've developed a whole flurry of apps, from simple add-ons to more complex stuff, mostly written in Python (3.6 at least). Check them out and feel free to download and use whatever you find useful.
BoxSVGGen - Generate cutouts (e.g. for a cutting device) for foldable boxes along with flaps and creases. Customizable X-Y-Z sizes and other parameters.
FloydSteinberg - A simple implementation of Floyd-Steinberg image dithering along with several palette samples.
FMR - Font mass rename, i.e. mass rename font files (TTF's) to their "real" name as specified in the corresponding data field in the file. Useful when there is a lot of TTF's named like 9028345.ttf, etc.
Palette - A PNG of many thousands of colors along with their names.
GFX2-3D - Convert images to 3D objects, by interpreting each pixel of the input image as the elevation.
GridGen - Generate graphical grids of various sizes, as transparent PNG's that can be merged and pasted over other images, e.g. like maps.
Harmaker - Generate sets of musical harmonies, with a given start one, selected at random however obeying the classical laws of common tones, transposition, etc.
LeGC - If you need a specific gear ratio in LEGO Technic but there are no suitable gears that would do the job directly, use this tool to find good approximating combinations of multiple gear systems.
MindControl - A full module to control LEGO NXT and EV3 programatically from Python, via Bluetooth - with generic firmwares. Can rotate motors and read sensors, all synchronously.
Neptune's Drums - A MIDI-to-ASIO sampler in realtime to be used as a substitute for electronic drums' sound. Customizable in many ways, but sorry - you will have to supply your own samples as we use the commercially purchased ones.
SpectralDraw - Convert an image to a sound spectrum in given time, which would look the same if the resulting sound was displayed in the spectral view of the sound editor. E.g. use Adobe Audition to open and observe.
Stewart - Calculations regarding positioning of Stewart platform. As long as you provide X-Y-Z displacement and three angles, you get the necessary extent of each actuator underneath.
Whatever is downloadable on this site, you can use for free. But if you found it useful, we appreciate getting a stimulant.