This page gathers some odds and ends for the original Starcraft in case this somehow becomes the last web server on the internet or something.
Insurrection and Retribution were two add-ons that were (inexplicably) officially authorized by Blizzard. Both feature a campaign for each faction as well as an assortment of multiplayer maps. Neither has been sold new since forever ago (and the companies involved are long since defunct). Occasionally "so bad, it's good," but mostly "so bad, it's bad."
These two add-ons weren't officially authorized but were sold commercially. They're also both pretty awful.