Tree of Life/Ages/Eternity
Central base "building"; has the usual 3 levels. Can move! Must "entangle" a gold mine to enable mining.
Provides food, health, and mana. Recovers mana at night; recovery rate is high enough that it completely recovers in less than one night.
Altar of Elders
Ancient of War
Produces basic combat units. Can move!
Defensive "building". Needs to be used with special care to be effective, primarily due to its minimum range. Can move! This allows you to move your Tower complex to defend your enemy's base from your enemy! Remember the end of the Battle of Helm's Deep?
Costs significantly more than the average "Tower" when the lost Wisp is considered.
Ancient of Lore
Produces (non-flying) spell-casters. Can move!
Ancient of Wind
Produces flying units (Hippogryphs and Dryads). Can move!
Produces the heavy flying unit.