Check out this link format post, the custom fields will only ask you for the title of the link, and the link itself. Then you can of course also add a description below, like this, using the normal textfield.
This is a single image post - the only difference to the gallery post is that it only shows one image, not multiple. Will be resized to 620px width, any height.
This is a chat conversation. Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat.
This is an aside format post, it basically only leaves out the title from the default format. You can still access the single page by clicking on the permalink (chain icon), bottom left. This format could be useful when you don't want a title, just text.
This is a test of a youtube video included by adding a link to the custom field.