The normal flags were getting a bit boring, so I created a Mutator Mod via Ravenscript [ravenfieldgame.com]that changes how they look like.
The custom flags will be automatically applied when the user plays on the map with the Custom Flags Mutator Mod enabled.
You can download the Mutator Mod here:
https://steamhost.cn/steamcommunity_com/sharedfiles/filedetails/?id=2078141525

Unity 5.6.7.1f/p
Ravenfield Modding Tools
The scene you want to have the Custom Flags on

Create three empty GameObjects and rename them "CustomFlagBlue","CustomFlagRed" and "CustomFlagNeutral".
Then add a Skinned Mesh Renderer to the GameObjects.
Now create the three materials with the "Flag" shader(found in Custom->Flag that should be included in the Ravenfield Modding Tools by default).
Finally just drag the materials onto the different Skinned Mesh Renderes.

How it should look like:

First you need to create a new empty GameObject. Do that by going to GameObject -> Create Empty

Great! Now make or just duplicate two more so that you have a total of three and rename them the following(Press F2 to rename) :
The naming order does not matter

IMPORTANT:: The names have to be named exacly like in the table above, or the material will be ignored!

You should have three Objects now


Now you have to add a "Skinned Mesh Renderer" to all of the objects. See picture

Now you should have three objects with a Skinned Mesh Renderer on it!

Now we will create the materials, that have the custom flag textures on them.
For that, create a new material:

Nice! Click on the newly created material if you haven't already, and then press on the Dropdown menu where it says "Standard". See picture


Select the "Flag" shader under the category "Custom"


The material should look like this in the inspector now:



Fantastic! Now just drag your texture on the empty "Texture" Square. See picture

You can play with the flag shader variables and even create a Translucency Color!


Note:If your texture doesn't fit onto the flag (like in the picture below) use the Tiling and Offset function of the Shader.

This step is pretty easy! Just drag the material onto the materials list of the Skinned Mesh Renderer.

Now do that for the remaining two and your all set!