I forgot to mention something that could be relevant as well. Depending on your operating system you can also visit the %APPDATA% or application data folder and browse to the presets folder.
The actual presets list is stored in the presets.ini file (on windows), and for example if you configure all your presets once, but you have to switch computers (with matching operating systems), you can take this file and replace it in on a different computer.
Under Windows10 you can go to: C:\Users\User\AppData\Roaming\Pencil2D\Pencil2D\presets to find the aformentioned file.