form field defined types:

fftHidden
fftText
fftTextArea
fftFile
fftDropDown
fftList
fftRadio
fftCheck
fftImage
fftButton
fftSubmit
fftReset
fftPassword
fftOtherTag

Forms are classes that extend tgsfForm which in turn extends tgsfHtmlTag.

Forms are required to implement 2 functions.
_setup()
_setupValidate( &$v );

form field groups:

$this->startGroup( 'Just a Caption' );

groups create (when using the built in top template) fieldsets with legends.
css classes are created from the captions, lowercase with underscores replacing spaces and other non standard characters.

To create fieldsets without a legend, prefix your caption with an underscore _

If you want to output labels and fields without using the built in form rendering and templates, you can use this syntax:

echo $form->fieldByName( 'example_field' )->getLabelTag()->render();
echo $form->fieldByName( 'example_field' )->getFieldTag()->render();