The core of a wand is a magical substance placed within the length of wood, usually extracted from a magical creature.

Types of wand cores:

Dragon heartstring
Unicorn tail hair
Veela hair
Fleur Delacour's wand
Thestral tail hair
Troll whisker
Coral
Thunderbird tail feather
Wampus cat hair
White River Monster spine
Rougarou hair
Horned Serpent horn
Snallygaster heartstring
Jackalope antler
Kneazle whisker
Kelpie hair
Basilisk horn
Bone
Newton Scamander's wand
Shell