Gandalf's staff, Ron Weasley's wand, Achilles' spear. All ash.
Ash has had a prominent place in many mythologies. It's Yggdrasil, the world tree, in Norse Mythology, connecting Heaven , Earth and Hel. Norse tradition also had the first man emerging from an ash tree.
In Greek mythology, when Peleus wed Thetis, the centaur Chiron presented them with an ash shaft that their son, Achilles, later wielded against Hector.
Pliny the Elder thought ash trees provided protection against snakes, writing that they would even avoid the shade provided by an ash tree.
Before wood was replaced by steel, ash was a prominent choice for farm equipment, tool handles, boat frames and weapons. Even the WWII aircraft the de Havilland Mosquito, nicknamed the Wooden Wonder, had ash components.
These days ash is under threat from the Emerald Ash Borer in the US and the fungus Hymenoscyphus fraxineus in Europe.