The Forbidden Worlds Add-on for Sins of a Solar Empire: Rebellion has 5 achievements.
Destroy 20 planets in a single game.
Control 20 different planet bonuses in a single game.
Occupy the 10 planet types simultaneously (Forbidden Worlds DLC required).
Fully specialize a Oceanic planet in social upgrades (Forbidden Worlds DLC required).
Fully specialize a Ferrous planet in industry (Forbidden Worlds DLC required).