The following Modules, while not necessary, are commonly used when creating Custom Content Types.
Automatic Nodetitles - Automatic Node Titles allows you to create custom title fields with the use of tokens so you can combine the first name and last name as the title field. Read more about the Automatic Nodetitle Module
Field as Block - This handy little module allows you to take a field and turn it into a Block that you can display in various field. A great way to simplify putting related content in the various regions of your site. Read more about Field as Block Module
External Links - External Links adds icons at the end of your links to indicate if the links point to an external site or is an email link. Read more about the External Links Module
Field Permissions - The Field Permissions module allows administrators to control who sees fields for your content types. For example, you might have a Content Type that captures an email address for the requestor, but you don’t want that information available to all people who view the site. Read more about the Field Permissions Module
Field Redirection - Redirects any field formatter for Link, Term Reference and Entity Reference fields that open a web page or URL. This module automatically redirects a page/node to the URL in the field entered. If no URL is entered in the field, the page/node is opened. A field settings widget is provided to allow selection of the appropriate HTTP status code. Read more about the Field Redirection Module
Fieldgroup - Allows you to create a group for fields created in your content type. Once enabled, the fieldgroup is created as a field and format to display is chosen. Then various fields that are part of that fieldgroup are added via drag-and-drop. Read more about the Fieldgroup Module