This is a suggestion:
PlaceholderAPI is a good API on the server, but your plugin does not support it, so I hope to support PlaceholderAPI, so get a lot of convenience can be used in PlaceholderAPI plugin.
Thanks

NametagEdit supports 2 popular placeholder plugins. See the code here. It'll work via the API or configuration (either mySQL/flatfile).

Please tell me the placeholders,thanks

This plugin does indeed support PlaceholderAPI as it states in the code (“PlaceholderAPI”)