What is a word that means helpful object or beneficial object so basically a noun which physically exists and is an antonym of hazard or obstacle?

Answer 1

An object doesn't necessarily have an antonym. You are looking for something physical, like a chair, a tree, or a pie. These words don't have opposites, there are different kinds of chairs, or trees, or pies, but the only opposite to a chair is no chair.

A physical thing that is a helpful object or a beneficial object is a tool. A tool is not limited to a hammer or an ax, a tool is also a pencil, a book, even water when used to wash or cook something; the computer that I am using to answer your question is a tool. After food, water, shelter, and fire, human's most helpful and beneficial object is a tool. Perhaps the opposite is tool-less.