Need a plugin where players can only type certain commands in safe zones only.  So like /shop can only be used in a safe zone.  Plugin could support any number of commands in a config file.

I wrote this up quick but haven't tested. Should work. GL.

using System;
using System.Collections.Generic;
using Oxide;
using Oxide.Core;

namespace Oxide.Plugins
{
    [Info("SafeZoneCommands", "Segfault", "0.0.1")]
    [Description("Commands that can only be used in SafeZone")]
    public class SafeZoneCommands : CovalencePlugin
    {

        private class SafeZoneConfig
        {
            public List<string> Commands;
        }

        private SafeZoneConfig SZC;

        protected override void LoadDefaultConfig(){
            Config.WriteObject<SafeZoneConfig>(new SafeZoneConfig() { 
                Commands = new List<string>() { "command.example" } }, true, nameof(SafeZoneCommands)
            );
        }
        public void Init() {
            SZC = Config.ReadObject<SafeZoneConfig>(nameof(SafeZoneCommands));
        }
        public object OnPlayerCommand(BasePlayer player, string command, string[] args)
        {
            if (player != null && !player.IsAdmin && player.InSafeZone() && SZC.Commands.Contains(command))
            {
                player.ChatMessage("This command can't be used within SafeZone!");
                return false;
            }
            return null;
        }
    }
}

Edited.. Noticed I did a few things wrong 

using System;
using System.Collections.Generic;
using Oxide;
using Oxide.Core;

namespace Oxide.Plugins
{
    [Info("SafeZoneCommands", "Segfault", "0.0.1")]
    [Description("Commands that can only be used in SafeZone")]
    public class SafeZoneCommands : CovalencePlugin
    {

        private class SafeZoneConfig
        {
            public List<string> Commands;
        }

        private SafeZoneConfig SZC;

        protected override void LoadDefaultConfig(){
            Config.WriteObject<SafeZoneConfig>(new SafeZoneConfig() {
                Commands = new List<string>() { "command.example" } }, true, nameof(SafeZoneCommands)
            );
        }
        public void Init() {
            SZC = Config.ReadObject<SafeZoneConfig>(nameof(SafeZoneCommands));
        }
        public object OnPlayerCommand(BasePlayer player, string command, string[] args)
        {
            if (player != null && !player.IsAdmin && !player.InSafeZone() && SZC.Commands.Contains(command))
            {
                player.ChatMessage("This command can only be used in SafeZone!");
                return false;
            }
            return null;
        }
    }
}

Thanks for giving it a shot!
I get this error when I try to compile the plugin on the server

(08:49:12) | Could not initialize plugin 'SafeZoneCommands v0.0.1' (Exception: Only access to oxide directory!

Path: /home/rust/pvetest/serverfiles/SafeZoneCommands)

at Oxide.Core.Configuration.DynamicConfigFile.CheckPath (System.String filename) [0x00029] in <50629aa0e75d4126b345d8d9d64da28d>:0

at Oxide.Core.Configuration.DynamicConfigFile.WriteObject[T] (T config, System.Boolean sync, System.String filename) [0x0000c] in <50629aa0e75d4126b345d8d9d64da28d>:0

at Oxide.Plugins.SafeZoneCommands.LoadDefaultConfig () [0x0001e] in <1836c789f64648c78f1db56120da17fe>:0

at Oxide.Core.Plugins.Plugin.LoadConfig () [0x00039] in <50629aa0e75d4126b345d8d9d64da28d>:0

at Oxide.Core.Plugins.Plugin.HandleAddedToManager (Oxide.Core.Plugins.PluginManager manager) [0x0000f] in <50629aa0e75d4126b345d8d9d64da28d>:0

at Oxide.Core.Plugins.CSPlugin.HandleAddedToManager (Oxide.Core.Plugins.PluginManager manager) [0x00000] in <50629aa0e75d4126b345d8d9d64da28d>:0

at Oxide.Plugins.CSharpPlugin.HandleAddedToManager (Oxide.Core.Plugins.PluginManager manager) [0x00000] in <60c318df79ed41688ea59335e48d61ad>:0

at Oxide.Plugins.CovalencePlugin.HandleAddedToManager (Oxide.Core.Plugins.PluginManager manager) [0x000b3] in <60c318df79ed41688ea59335e48d61ad>:0

at Oxide.Core.Plugins.PluginManager.AddPlugin (Oxide.Core.Plugins.Plugin plugin) [0x00027] in <50629aa0e75d4126b345d8d9d64da28d>:0

at Oxide.Core.OxideMod.PluginLoaded (Oxide.Core.Plugins.Plugin plugin) [0x00035] in <50629aa0e75d4126b345d8d9d64da28d>:0

Issue seems to lie in your config handling.

If you remove

nameof(SafeZoneCommands)

It compiles

Line 26

public void Init() {
    SZC = Config.ReadObject<SafeZoneConfig>();
}

However, ideally you wouldn't read the config in Init() instead you would do that in LoadConfig. Example:

using System;
using System.Collections.Generic;
using Oxide;
using Oxide.Core;

namespace Oxide.Plugins
{
    [Info("SafeZoneCommands", "Segfault", "0.0.1")]
    [Description("Commands that can only be used in SafeZone")]
    public class SafeZoneCommands : CovalencePlugin
    {

        private class SafeZoneConfig
        {
            public List<string> Commands;
        }

        private SafeZoneConfig SZC;

        protected override void LoadConfig()
        {
            base.LoadConfig();
            try
            {
                SZC = Config.ReadObject<SafeZoneConfig>();
                if (SZC == null) throw new Exception();
            }
            catch
            {
                LoadDefaultConfig();
            }
        }

        protected override void LoadDefaultConfig()
        {
            SZC = new SafeZoneConfig() 
            {
                Commands = new List<string> { "command.example" } 
            };
        }

       protected override void SaveConfig()
       {
           Config.WriteObject(SZC);
       }

        public object OnPlayerCommand(BasePlayer player, string command, string[] args)
        {
            if (player != null && !player.IsAdmin && !player.InSafeZone() && SZC.Commands.Contains(command))
            {
                player.ChatMessage("This command can only be used in SafeZone!");
                return true;
            }

            return null;
        }
    }
}

@0x89A thanks for pointing that out. Been a while since i made a plugin, however I've recently started getting back into rust.