Chorus supports add-ons, but at a generic level. As each add-on does things differently, not all functionality will be available. The Add-Ons page lists add-ons that are executable (eg. Global Search) or add-ons that provide a list of audio/video content (eg. YouTube). Add-ons that provide lists can also be accessed via the browser.
Out of the box, Chorus includes search functionality for some of the more popular add-ons, this allows you to search content provided by that add-on via the search page. For example you could type in "crazy cat videos" in the search box and then on the search page, click "YouTube" to get a list of videos provided by YouTube on that subject.
If you wish to search content provided by an add-on that isn't included with Chorus, you can add your own custom add-on search which tells Chorus how it can search for the content provided by that add-on.
To add a custom search, you need to know what url the add-on is using internally to provide the search results. This
isn't always easy or obvious to find out and may involve looking through the add-on code or kodi logs to determine the
correct url to use. Chorus will substitute the token [QUERY] with the search term.
plugin://plugin.video.youtube/search/?q=[QUERY]plugin://plugin.audio.soundcloud/search/query/?q=[QUERY]plugin://plugin.audio.radio_de/stations/search/[QUERY]plugin://plugin.audio.mixcloud/?mode=30&key=cloudcast&offset=0&query=[QUERY]If you find a good custom add-on search that should be included in Chorus out of the box then you should consider submitting a pull request for it. Look at the SoundCloud module as an example of the code structure. NOTE: Only add-ons that are in the official repository will accepted.
Chorus provides a settings page for enabling and disabling add-ons, be aware that disabling certain add-ons may have adverse effects so use with care.
A few things that have been observed with using add-ons in Chorus