Games Workshop/Citadel Miniatures produced the popular Heroquest boardgame in conjunction with Milton Bradley in the 1980s. Heroquest (and some of its expansion packs) featured solid-based plastic Citadel miniatures as part of the game components. Some expansion sets (Kellar's Keep, Return Of The Witch Lord) utilized only figures from the basic Heroquest boxed set.
Barbarian Quest Pack (The Frozen Horror)
Elf Quest Pack (The Mage of the Mirror)
Against The Ogre Horde