I later found that, there is an official way to see all the routes, by going to http://localhost:3000/rails/info/routes. Official docs: https://guides.rubyonrails.org/routing.html#listing-existing-routes
Though, it may be late, But I love the error page which displays all the routes. I usually try to go at /routes
(or some bogus) path directly from the browser. Rails server automatically gives me a routing error page as well as all the routes and paths defined. That was very helpful :)
So, Just go to http://localhost:3000/routes