In-Game Whitelist provides a new way to whitelist people. When someone joins the server, they cannot move. They will not be able to move until a person adds them to the whitelist.
Commands:
/addplayer
[playername] - Adds the player to the whitelist.
/removeplayer [playername] - Removes the player from the whitelist.
(Keep in mind, this is my first plugin. So, if something doesn't work, please report it in the issues tab.)