I’m not sure how this could be easy without adding a full-on vector software to the UI. There are already open source software packages that do this, I really don’t think this is something HA should be able to do.
I definitely could get behind a way to add already created vector files to HA. But any kind of GUI that creates them from scratch should be off the table. This is a home automation software after all.
There is free software that will allow you to create an SVG file. SVG files work really well on websites regardless of the screen size because the image scales easily.
Once the SVG File is created, the icon selection process should include a way to upload an SVG file and use that image.
Inkscape can be used to create svg files.
HA have some requirements, but it can be handled with an edit of the svg file.
I made my compass arrows for my weather card that way.
I can’t fully remember the method, but I will read up on it and then post a guide.
Someone can then take that an improve it.
1000% Yes! I don’t know why there even needs to be integrations like Font Awesome and Simple Icons. Custom icons that source from all available icon sources (local and/or Internet) should be in Core.