Any mob that has a head has a 1% change of dropping it upon death.
New Player Heads now render the overlay! And also have a 1% chance of dropping
You can use an Ender Scythe to have a 100% change of head dropping.
They can be worn or used as decoration.
If you have Twilight Forrest and/or Thermal Expansion 3 you'll be able to collect heads from most of the mobs added by those mods!
I'm also open to requests :)
How to Get:Edit
You get them by killing mods (Like: Spider, Pig, ETC) Using the Ender Scythe.
Without it, Theres 1% Chance it drops when a mob dies.
When fans asked For a spread mod with heads, ganymades01 made The Headcrumb mod, With an special addition - Player mobs (Sadly hostile) And their heads.