Here is the full list of all 12 Lost Artifacts: Time Machine trophies - there are 7 bronze, 4 silver and 1 gold.
For fixing the portal
For catching the kraken
For getting rid of the Bandit
For restoring time altars
For activating the portal
For speeding up workers
For speeding up construction
For stopping time
For defeating the Villain
For catching 30 mammoths
For catching 30 skeletons
For completing all levels with 3 stars