PhilHilton

Adds shortcode for including a custom field on a page or post. 
Create a custom field on your post/page. Then use the following shortcode to include it on your site:
[embed_custom_field “field-name-here”]
This is useful for arbitrary bits of text or code that you don’t want the WYSIWYG editor to mangle and reformat.
This may work fine with versions older than 3.9.0 (and almost certainly does) but it has not been tested.
<ul>
<li>Note that the Gutenberg blocks content editor includes a “Custom HTML” block type, which negates the need for this plugin. It will NOT be maintained after December 31st, 2019.</li>
</ul>

Embed Custom Field

Adds shortcode for including a custom field on a page or post. Note that the Gutenberg blocks content editor includes a "Custom HTML" block  …

aThemes

vladff

The Sydney Toolbox plugin is meant to be used only with the Sydney WordPress theme.
This plugin registers custom post types and custom fields that are needed in the <a href="https://wordpress.org/themes/sydney/" rel="ugc">Sydney theme</a>

Sydney Toolbox

Registers custom post types and custom fields for the Sydney theme

Embed Custom Field vs Sydney Toolbox