This plugin allows players to change the color of their name as it appears in the tab list and also in text chat.
This does not affect the color on scoreboards or floating above their heads so I would still recommend setting up teams as per vanilla to get a baseline that is similar to what you will set with this.
Usage:
This plugin has one command /name_color
Example:
/name_color set playername ff00ff
This will set the name color of the player to Magenta
/name_color clear playername
This will remove any set color for the player restoring the default formatting of minecraft
Permission to use the command is:
name_color.permission
This plugin requires a Paper server to run, it will not run on Bukkit or Spigot Servers