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

There isn't one perfect word that captures all those nuances, but here are some options depending on the specific context:

General:

* Tool: This is a broad term that encompasses any object designed to help with a task.

* Asset: This implies something valuable and helpful, but it's not always physical.

* Resource: This refers to something available for use, and can be either physical or intangible.

More specific:

* Aid: This implies something that helps in a specific situation.

* Appliance: This refers to a machine or tool designed for a particular task.

* Device: This is a more general term for a piece of equipment, but can be specific to a particular function.

Antonyms for hazard/obstacle:

* Advantage: This implies a positive situation or condition that helps you succeed.

* Benefit: This implies something that provides a positive outcome.

* Opportunity: This implies a chance to do something beneficial.

The best word to use will depend on the specific situation and the context.