Marko Heijnen

CodeKitchen

At this moment it only adds a gallery endpoint to posts with only one theme. In the next couple of weeks I will be looking at more solutions and build themes around those. I will then also start building a settings page where you can select what the default theme is and build a metabox where you can select per post what the options should be.
A demo can be seen at https://fesere.de/. If you go to https://fesere.de/african-wildlife/ you see it’s a gallery provided by the theme and gets extended by this plugin. So when you go to https://fesere.de/african-wildlife/?fullscreen you see the same images but without the rest of the site. The plugin is so build that it should easily integrate in your existing theme.

Fullscreen Gallery

A simple plugin that adds a fullscreen endpoint to display the gallery images

Toni

This plugin enables you to display a Fullscreen Button on your site. The plugin can easy implement with a shortcode. 7 different Versions from the Fullscreen Button are current available.
<h3>Usage</h3>
Integrate the Shortcode in WordPress and you get the following Unicode Symobol ⛶ with the Full Screen Function. Full customize, for changing the size or color. The ⛶ Unicode Symbol works with the standard HTML text formats.
Update: Now with Support for Font Awesome. With a special Shortcode you get the Font Awesome Expand Icon for Fullscreen Mode.
Shortcodes:
Fullscreen Button (Unicode Symbol ⛶) [fullscreen_button] 
Fullscreen Button (Unicode Symbol 🡥) [fullscreen_button_2] 
Fullscreen Button (Unicode Symbol ↕) [fullscreen_button_3] 
Fullscreen Button (Font Awesome) [fullscreen_button_fa] 
Fullscreen Button (SVG Alternate) [fullscreen_button_a1] 
Fullscreen Button (Text Version) [fullscreen_button_text] 
Fullscreen Button (Switch Toggle) [fullscreen_toggle]

Fullscreen-Button

Fullscreen Button Plugin, with a stylable Unicode Symbol for your WordPress.

Fullscreen Gallery vs Fullscreen-Button