The first was Library of Leng, first printed in Limited Edition Alpha , whose text says, There is no limit to size of your hand. In subsequent reprintings, most notably in Revised Edition , the text was changed to You must skip the discard phase of your turn--as if that was a bad thing
It is also one of the best tempo dorks you can cast on two which is ideal on a card filling a utility role
We probably need a lot more artifacts before Underhanded Designs is worth it, and even then, its not as exciting as Inventors Apprentice
Maze of Ith or Nykthos, Shrine to Nyx - remember to activate it in their upkeep so they cant use those lands to do what they expected it to do for the remainder of the turn
By using the Commander Deck Building Template fully, or even just as a starting point, you should have no problems learning how to build a Commander deck