Yevhen Horbyshyn

This plugin adds a hidden “inverted” checkbox to your forms to prevent bots from submitting them.
<ul>
<li>Adds support for Contact Form 7 via shortcode <code>[ica_checkbox]</code></li>
<li>Adds JavaScript-based hidden checkbox to regular forms in the footer</li>
<li>Blocks form submission if the checkbox is unchecked or missing (typical behavior for bots)</li>
</ul>

Inverted Checkbox Antispam

Simple spam protection using an inverted checkbox. Compatible with Contact Form 7 and custom HTML forms.

Moove Agency

Use radio buttons or checkboxes for your categories and custom taxonomies with this incredibly powerful, easy-to-use, well supported and 100% free WordPress cookie plugin.
(Please note that the “select all” functionality can work with checkboxes only.)
<h3>Testimonials</h3>
★★★★★
<blockquote>
“Works perfectly!” – <a href="https://wordpress.org/support/topic/works-perfectly-1565/" rel="ugc">IamRJO</a>
</blockquote>
★★★★★
<blockquote>
“Very helpful. Easy to use.” – <a href="https://wordpress.org/support/topic/very-helpful-easy-to-use-4/" rel="ugc">cardofearing</a>
</blockquote>
★★★★★
<blockquote>
“Exactly what I was looking for.” – <a href="https://wordpress.org/support/topic/exactly-what-i-was-lookng-for/" rel="ugc">marketmeau</a>
</blockquote>
<h3>About us</h3>
<a href="https://www.mooveagency.com/" rel="nofollow ugc">Moove Agency</a> is a premium supplier of quality WordPress plugins, services and support. <a href="https://www.mooveagency.com/services/wordpress-development/" rel="nofollow ugc">Visit our site</a> to learn more.

Select All Categories and Taxonomies, Change Checkbox to Radio Buttons

Thanks Moove for this handy plugin.  Haven't used it long but it helps with clients who are having trouble with Categories / Custom Taxomies.  This helps with the confusion. If you're a developer, this is a handy little tool to install before handing off a website to a client.

Very helpful. Easy to use.

I used it years ago and it was well done. 

But for now it seems to stoped working with newer wordpress versions (with classic editor plugin):

- Wrong Term in Radio list is selected on Editpage Loading, saves the wrong term on update.
- Button [+ Add Term] adds an uneditable id number

maybe in this area there had been changes to the wordpress API that should be updated here.

Was very good

Use radio buttons or checkboxes for your categories and custom taxonomies with this incredibly powerful and easy-to-use plugin.

Inverted Checkbox Antispam vs Select All Categories and Taxonomies, Change Checkbox to Radio Buttons