These fields can only be used by forms published in iCM. You'll see them in article extras and subsite configuration.
Asset Lookup - Multiple
Select one or more iCM assets of a particular type (articles, media, users etc) in a multi-line list box.
Asset Lookup - Single
Select an iCM asset of a particular type (article, media item, user etc).
Code Editor Input
A code editor field.
Textarea Input - WYSIWYG CK
A WYSIWYG text area input field that uses CK Editor, matching the article text editor.
