Alphabetical list with map and difficulty rating: here
Events are repetitive, they come again from time to time. Room progress and charges remain in your account and are listed again when the concerned event is active. Multiple collected items also remain in the account but are not counted for the new event, i.e. you have to collect them again.
Please remember: NEVER ever assemble an artifact by means of the popup that occurs when you find the last needed item. Always wait for the assembly task at the left side!