Beheaded is a mod that adds the ability to get any head from any mob.
Beheaded uses the config file to change head drop rates, allowing you to control the rates depending on your purpose. By default, they are all at 10%.
All the heads are 3D models both inside the inventory and out. You can even wear them like a helmet, too!
By default, Beheaded comes bundled with a handful of heads from vanilla. If you wish to add more, from mods or other vanilla mobs, you can create the image yourself and put it into the .jar file, and Beheaded will pick it up automatically.
Keep in mind this mod requires SourceCodedCore, found here