The Peaceful Plus mod allows you to craft various items normally found while playing on higher difficulties. Well if you’d rather not deal with mobs and still want to utilize the items they drop, then this mod gives you that opportunity.
With the ability to craft these items you can craft all different heads as well. You’ll randomly find bones to craft skeleton skulls.
Rotten flesh crafted from spider eyes and beef will give you zombie heads.
Gunpowder gives you creeper heads.
Wither bones will give you wither skulls.
And beef and pork will give you human heads.