An alternative option to receive Bones is to put blocks of Fossils into a Processor. Fossils can be found on the Fossil layer underground, easily to reach by wandering into most Caves. Also recesses near rivers might have blocks of Fossils visibly accessible to take.
To mine Fossils, no Power Cell has to be equipped since R39 in February 2017. With the same update it has also become possible to put Bones into a Forge (together with some Fuel) to recreate blocks of Fossils. The balance is still not fixed, but for now you can forge 4 blocks of Fossils from 1 Bone each.
Since R35 in October 2016, bones can also be used to craft special Halloween - blocks and items like Haunted Walls, Haunted Stone Walls, Haunted Floors, Haunted Stairs, Carpeted Haunted Stairs, Haunted Roofs, Haunted Lamps, Haunted Gravestones, Haunted Doors and Haunted Pumpkins from rare crafting recipes that can only be scavenged by hunting and killing ghost creatures that appear at (ingame-)night during Hallween event times.