I would like to fill my geometries while designing symbols with patterns like dots, lines, and so on.
I know it is possible on the PCB, like in the screenshot below, but what about symbols? I’m seeing the fill option in the graphic properties, but there’s only the solid color as the fill option.
Add Zone (Ctrl+Shift+Z) and on the right change Fill type from Solid Fill to Hatch Pattern.
The effect should look like that:
EDIT: Sorry didn’t read your post properly that you ask about symbols 
but what about symbols?
There is no builtin option for filling shapes with a pattern in schematic editor and symbol editor.
Is it a thing that could be implemented in the future?
It’s been implemented for a long time…
Just create a New Symbol and draw Lines, Circle (filled or unfilled), Curves…etc… example screenshot below… (Also, you can Draw it in some other program (such as LibreOffice/etc) and use Kicad’s Image-Converter to Export as Symbol… )
I did not fuss with making it pretty or with Diagonal lines… I did fill the Dots with different color than the line color…
(Added Filled with Color)
