Name some of the most commonly used angular directives, with description?

ng-app:

     Declares the root element of an AngularJS application, under which directives can be used to declare bindings and define behavior.

ng-bind:

     Sets the text of a DOM element to the value of an expression. 
For example, <span ng-bind="name"></span> will display the value of ‘name’ inside the span element. Any changes to the variable ‘name’ in the application's scope are reflected instantly in the DOM.

ng-model:

    Similar to ng-bind, but establishes a two-way data binding between the view and the scope.

ng-model-options:

    Allows tuning how model updates are done.

ng-class:

    Allows class attributes to be dynamically loaded.

ng-controller:

    Specifies a JavaScript controller class that evaluates HTML expressions.

ng-repeat:

    Instantiate an element once per item from a collection.

ng-show & ng-hide:

    Conditionally show or hide an element, depending on the value of a boolean expression. Show and hide is achieved by setting the CSS display style.

ng-switch:

    Conditionally instantiate one template from a set of choices, depending on the value of a selection expression.

ng-view:

    The base directive responsible for handling routes that resolve JSON before rendering templates driven by specified controllers.

ng-if:

    Basic if statement directive which allow to show the following element if the conditions are true. When the condition is false, the element is removed from the DOM. When true, a clone of the compiled element is re-inserted