Free Update : Safezone gmod 3.1 (2021) - Originahl Scripts by Norda

Script link : https://osgmod.com/gmod-scripts/1364/safezones-systems

The safe zone system allows players to avoid damage from other players.

You can also :
Remove weapons from the incoming player's inventory.
Deactivate weapons,
Deactivate player damage,
To remove the npcs inside,
To delete the Nextboxes inside since version 3.1.

More scripts here : https://osgmod.com/gmod-scripts/page-1