Application Wizard comes with a set of seven predefined group icons, but you can also assign custom icons to groups if you like.
Open Application Wizard.
On macOS 13 or later, choose Application Wizard > Settings. On macOS 12 or 11, choose Application Wizard > Preferences. Then click Groups.
Select the group in the list and choose Other from the Choose Icon drop-down menu.
Select an icon from a custom set or an ICNS icon file or select any of the items (disks, folders, applications, documents, ... ) on your computer to use its icon. Click Choose.
Great icon collections can be freely downloaded from Iconfactory.