Google Chrome Extension to submit POST/GET requests?

Simple REST Client. No frills, gets the job done.

You can try POSTMAN.

It works good for making HTTP requests and debugging and I like its UI.

DHC - Dev HTTP Client

"REST & HTTP API developer's pocket knife. Easy to use and configurable. HATEOAS, Hypermedia, Requests History+Repository, and more."

I find it very useful and it has many features.