Magento 2: available field types in system.xml

Question

What are available values for field types in etc/system.xml configuration file:

<?xml version="1.0"?>
<config
        xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
        xsi:noNamespaceSchemaLocation="urn:magento:module:Magento_Config:etc/system_file.xsd">
    <system>
        <section id="...">
            <group id="...">
                <field id="..." type="???">
                    ...
                </field>
            </group>
        </section>
    </system>
</config>

Answer 1

Magento 2 system configuration provides below fields type.

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

Answer 2

Looking at the file /lib/internal/Magento/Framework/Data/Form/Element/Factory.php (sources on Github, for Magento 2.2 & 2.3), 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.

Answer 3

Magento 2 docs.

text Standard, single row text field

textarea Text block

select Normal dropdown, may need a custom source_model. Also used for Yes/No selections. See Magento\Search\Model\Adminhtml\System\Config\Source\Engine for an example.

multiselect Like select but multiple options are valid.

button A button that triggers an immediate event. Requires custom front-end model to define the button text and the action. See Magento\ScheduledImportExport\Block\Adminhtml\System\Config\Clean for an example.

obscure A text field with the value encrypted and displayed as ****. Changing the type using “Inspect Element” in the browser does not reveal the value.

password Like obscure except that the hidden value is not encrypted, and forcibly changing the type using “Inspect Element” in the browser does reveal the value.

file Allows a file to be uploaded for processing.

label Displays a label instead of an editable field. Use this type when a field is editable only on specific scopes, for example Store View level only.

time Control to set time using three dropdowns–Hour, minute and second.

allowspecific A multiselect list of specific countries. Requires a source_model such as Magento\Shipping\Model\Config\Source\Allspecificcountries

image Allows an image to be uploaded.

note Allows an informational note to be added to the page. This type requires a frontend_model to render the note.