Treasury: Increase gold capacity of each tile by 1/3
Lair: Reduce changes of infight, increase time between
unconcious to
dead a bit for your creatures.
Hatchery: Improved chickens. Creatures need fewer chickens to become full.
Training Room: Increase level cap to 5. Simple as that.
Library: No Upgrade, since i assume upgraded rooms would be researched here its an upgrade enough that they can upgrade rooms.
Workshop: Trap production its slightly faster and attack power of melee units its slightly better.
Guard Room: Increase guard range.
Prison: Prisioner cap and skeleton cap increased by 1/3
Torture Chamber: Slightly faster convertion.
Temple: I Dont Know!!!
Graveyard: Max Vampire cap upgraded by 1/3
Combat Pit: Increase max level cap to 9