ijmccallum

This theme demo / theme switcher plugin will add a bar to the top of your WordPress site listing every theme you have installed. It gives visitors the ability to switch between themes and try out their look on your live site.
After installation it requires no set up, it just works.
If you would like to see any extensions to this theme switcher please don’t hesitate to contact me from my website or post something in the support section. And, if you like it – please leave something nice in the review section! The more popular this becomes the more likely I’ll be to work on giving it lots more extra awesome.
<h4>Why another theme switcher?</h4>
I built this theme switcher primarily for myself. There are a number of other theme switchers out there but they all require visitors to click on a drop down menu then select a theme to demo or have some other complication and none of them had the clean, simple, minimal way of switching that I was hoping for in a theme switcher. So I built this theme switcher to give visitors an instant list of all the themes I hope to develop which they will be able to demo in a single click, also it doesn’t need any set up so it’s very easy!
So, I imagine most of the people interested in this theme switcher would be theme developers but if there are any people who are really indecisive about how they want their website to look, I guess this could provide them with an interesting solution to the website design problem. Let me know if you can think of any other uses for a theme switcher!

IJM Theme Switcher Bar

Add a theme switcher / theme demo bar to your site. Allows users to switch the theme they see on your site.

Ermald Billa

Improve Accessibility – Dark Mode Switcher for WP adds a professional dark/light mode toggle to your WordPress website.
Features:
<ul>
<li>Universal dark/light mode toggle</li>
<li>localStorage support for user preferences</li>
<li>Modern responsive design</li>
<li>Full WordPress security implementation</li>
<li>JavaScript API for developers</li>
<li>Mobile-friendly</li>
<li>Translation-ready</li>
</ul>
Security:
The plugin implements all WordPress security standards including nonces, sanitization, escape output, and permission checks.
Developer API: 
 `javascript 
// Get current theme 
window.iadsAPI.getTheme();
// Change theme 
window.iadsAPI.setTheme(‘dark’);
// Toggle theme 
window.iadsAPI.toggleTheme();

Improve Accessibility – Dark Mode Switcher

A secure WordPress plugin to add a universal dark/light mode toggle with localStorage support.

IJM Theme Switcher Bar vs Improve Accessibility – Dark Mode Switcher