For 1.16 and above hex codes can be supported. Using this color format will make the plugin look beautiful on the server. It will also introduce a new feature for the user.

Besides, adding placeholders would be useful in many ways. (For example: Servers with texture packs can perform different operations on these items. Or they can show information about the group they created...)

Hello sorry, but what do you actually mean by placeholders in items? Do you mean custom NBT?

No, I'm talking about using placeholders like %player% in item names.

Everything suggested here should now be added to the plugin in the latest development builds.