Plugins that I (sometimes with others) have contributed to the Omeka Community.
Shortcode embeds code for creating linked carousels, one with thumbnails and one with full image. The thumbnail carousel can be used to navigate the full image carousel. You can also just have a carousel of full size images you can click through. Also contains code for embedding in Exhibits.
A shortcode that allows you to insert any file associated with an item or a file from the images directory of your current theme into a Simple page or the text area of an exhibit. This allows you to display file images of logos and similar images where ever you need to without creating an item for that image. Just put the image in the images directory of your theme and reference the file name with this shortcode.
KalturaVideo is an Omeka plugin that allows you to stream video from either Kaltura Mediaspace or Youtube. In an item in Omeka, this video stream can have start and end points set in it allowing you to divide the stream into segments. Since each item in Omeka can contain a video segment, you can describe that segment using all the metadata fields available in Omeka for an item such as Description, Creator, Date, etc.
Video Stream is a plugin for Omeka that embeds a JW Player video segment player into item show pages. JW Player is a largely used open source video player that can be used with any device. It supports a lots of protocol and can be customized with a lot of options for configuration.
Similar to the Video Stream plugin but uses the shortcode pattern to implement. As a shortcode, this can be used to insert video in Simple Pages as well as basically anywhere you can use html. In addition, it contains the code to use with Exhibits allowing you to insert a video block on an Exhibit page.
If you are using or are considering using Indiana University's Samvera=based media server platform, this plugin allows you to embed Avalon iFrames in Omeka pages and exhibits.