Content (shortcodes) and portability

I have a site running on one of your themes that needs to be moved to another theme (not one of yours I’m afraid). There are quite a few shortcodes in use on the site so I was wondering if your shortcode function is based on a plugin, freely or commercially available.
Editing all the shortcodes to make the content work with a new theme will be quite a bit of work so if there is a plugin available that can handle them it would make the transition much easier.

(Sent you a mail with this question a few days ago but didn’t get a reply, hence posting it here)

All the best, Thorir