Looking at the file /lib/internal/Magento/Framework/Data/Form/Element/Factory.php (found here on Github, for Magento 2.2-develop), one can find the following default list of elements, as specified by Amit in his answer:
// Factory.php, lines 26-55
protected $_standardTypes = [
'button',
'checkbox',
'checkboxes',
'column',
'date',
'editablemultiselect',
'editor',
'fieldset',
'file',
'gallery',
'hidden',
'image',
'imagefile',
'label',
'link',
'multiline',
'multiselect',
'note',
'obscure',
'password',
'radio',
'radios',
'reset',
'select',
'submit',
'text',
'textarea',
'time',
];
If Composer was used to install Magento, the data may also be found in /vendor/magento/framework/Data/Form/Element/Factory.php, as mentioned in Mohit's comment below.