Usage: fastfetch -c <file>

Loads a config file. A config file contains one flag per line. Empty lines or lines starting with # are ignored.
If the file is relative it looks in the following order:
   - relative to the current working directory
   - relative to ~/.local/share/fastfetch/presets/
   - relative to /usr/share/fastfetch/presets/
Fastfetch provides some default presets. List them with --print-available-presets.
Note that this will only print presets fastfetch knows about and not every possible one.