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.

Seth Smigelski

Slim Mobile Theme Switcher is a developer-friendly, lightweight solution for sites that need a dedicated mobile experience without the overhead of a heavy mobile plugin. This plugin targets mobile handhelds, ensuring tablet users may still enjoy your full desktop-grade layout.
<h3>Key Features</h3>
<ul>
<li>True Mobile Detection: Uses refined regex to separate small-screen phones from tablets (iPads/Android tablets).</li>
<li>Manual Overrides: Allow users or testers to force a view using <code>?theme=handheld</code> or <code>?theme=active</code>.</li>
<li>Persistent Choice: Option to remember a user’s manual theme choice for 30 days via cookies.</li>
<li>No Bloat: Zero front-end CSS or JS added by the plugin itself.</li>
<li>Developer Friendly: Built by a developer for developers.</li>
</ul>
<h3>How It Works</h3>
The plugin uses a precise, two-step detection process to ensure the best user experience: 
1. Exclude Tablets: High-resolution devices (iPads, Android tablets, Kindle Fire) are served the Desktop Theme to take advantage of their screen size. 
2. Detect Phones: Handheld mobile devices (iPhone, Android Mobile) are served the Mobile Theme. 
3. Manual Choice: If a user manually switches via URL, their choice is honored for 30 days via cookies.

Slim Mobile Theme Switcher

Serve a mobile theme to phones while keeping desktops/tablets on the primary theme. Lightweight mobile theme switcher with modern device detection.

IJM Theme Switcher Bar vs Slim Mobile Theme Switcher