FirstJoinProtect

Please not that this is a nearly exact copy of this plugin, to prove that it isn't difficult to make a plugin like that. I'm not saying that developer did a bad job, I'm just saying that his plugin isn't worth the 3.90 USD at all.

With this plugin, you can protect your players who first logged into your server. Now they can finally build their house, craft the sword and armor!
This is the second plugin in the network that makes mobs passive for you while you are protected!

Features:

• This protects you from the players.
• The monsters do not target you, but if you hit them, they will attack you
  
• All messages are customizable
• Time of protection in ActionBar
  
• Processing players in a separate thread, which makes the load on the server minimal!
  
• If your server is restarted or the player has left game, the protection time is saved!
  
• It supports mobs from MythicMobs and other custom mobs

Commands:

Permission:
[protect.enable] - Allow to use command /protect enable <time>
[protect.enable.others] - Allows to use command /protect enable <player> <time>
[protect.disable.others] - Allows to use command /protect disable <player>
[protect.reload] - Allow to user command /protect reload
/protect disable - No need permission

I'd like to thank @baksovic for releasing this plugin way overpriced, and giving me a great way to spend 2 hours. Yes, this plugin took me 2 hours. Including long breaks. 2. Hours. That's not enough time to be worth money when it comes to Spigot plugins.