Some Fritzing parts, I've made for my projects. I only use Fritzing as a pictorial layout drawing (not for schematic or PCB) so it only has the breadboard view with the associated connectors
To import a part in Fritzing, go to "Mine" on the right drawer then import and pick the .fzpz file located in each part folder
The process is to create the svg with a software like Inkscape and importing it in the "part editor" of Fritzing. The svg should have a group <g id="breadboard"></g> (also a <g id="icon"></g> for the icon) and identify the connector that are mapped in Fritzing by connectorXpin in svg with id="connectorXpin". Note that in Fritzing it shows connector1 in the connector tab of "part editor" but it should be id="connector1pin" inside the svg (note the suffix pin)
In Inkscape, save as Optimized SVG before importing to Fritzing. If svg has text, the font size can't be set with styles attributes but with font-size and not in px, for instance in Metec Braille line 20 cell part, replace font-size:1.76px with font-size:2 before importing.
Part file reference : https://github.com/fritzing/fritzing-app/wiki/2.1-Part-file-format
The MIT License (MIT) Copyright (c) 2018 Bertrand Martel