I was wondering what was the name of that plugin that created customizable text floating which looks exactly to a Minecraft plugin https://dev.bukkit.org/projects/holographic-displays

At first, I thought it was a private custom made plugin but then I saw dozens of other servers I have it as well. I searched around on forums and multiple plugin provider websites but couldn't find it. does anyone know the name of that plugin or got a link to its page?

misticos

This is not a specific plugin, it is a ddraw command that is sent by plugins. And it requires admin flag so plugins temporarily grant you one.

And for that work you need specific plugin....

At first, I thought it was a private custom made plugin but then I saw dozens of other servers I have it as well. I searched around on forums and multiple plugin provider websites but couldn't find it. does anyone know the name of that plugin or got a link to its page?​

Well because its mostly private, and easier here to hire/ask developer to make it for you