There are a number of modules that integrate with Fields API. Some are field modules that allow you to create specific kinds of fields. Others are helper modules that add functionality to Fields. As with all contributed modules, modules created by other developers are not official and may or may not work.
The Views module is not a part of the Field module, but is a great compliment to it. Views allows you to filter, sort and display your custom fields in numerous ways.
If you have problems or questions about any module, get help on their own project pages using the links below.
You can see a current list of modules that have been tagged as a part of Fields on the Downloads Page.