Found this bit of code over at old oxide forums and well I am not that great at coding lol.

// Steam ID of the profile you want to use the icon from
        string ID = "76561198872518477";
        object OnServerMessage(string message, string name, string color, ulong id)
        {
            // Loop through all connected players
            foreach(var player in BasePlayer.activePlayerList)
                // Send a message to all of the connected players with the new steam ID
                rust.SendChatMessage(player, name, message, ID);
            // Returning a value so it stops the original, unmodified message from being sent
            return true;
        }​

Now when I create it as a cs file and drop it in plugins I get this error:

Error while compiling: OnServerMessage.cs(4,8): error CS1525: Unexpected symbol `string'

I dug around unity code and seems maybe { is wrong?

Yup thats exactly what I was looking for. I guess I wanst entering the right keywords in plugin search. lol
Thanks Wulf.

It was in queue, just approved. :P

Trying it out now. But looks like it just works only for server console chat :(
Doesnt change icons for other server messages like players joining, PlayerRanks, and AdvertMessages etc.

You won't be able to change those from another plugin, those are sent directly from the plugins, not a server message.

Gotcha. Thougt maybe they hooked through server  messages which caused them to use default Rust icon.
I will have to dig around and see about editing those plugins.
I saw another server using a different Icon for advert mesages and such and figured I would see if I could figure it out.

OnServerMessage only handles messages sent by Rust itself. Everything else is sent directly.