Thanks Phoenix124 for scribdl and BlueHatbRit for mdpdf
Make sure you're using Python 3 (Python 2 is not supported by a few dependencies). Then run these commands:
**macOS prerequisites for md2pdf / cairo
$ brew install cairo
$ brew install pango
$ brew install libmagic
$ brew install gtk+
Make sure you python Pillow is up to date > 6
$ python3 -m pip install --upgrade pip
$ python3 -m pip install --upgrade Pillow
$ pip install scribd-downloader
**Install mdpdf
$ pip install mdpdf