All things considered, Sauron, the Dark Lord is the best and most flavorful of those four
However, depending on the specific strategy of the deck, other cards like Mayor of Avabruck or Huntmaster of the Fells could be considered as potentially better options
Putting a fourth oil counter on Ichor Synthesizer after it has become blocked will not cause it to become unblocked
But yeah, like the rest of the overcosted common Room cards here, we ain't seeing this anywhere outside Limited
The four Secret Lair drops, which reprint existing MTG cards in limited quantities, will correspond to the four seasons starting with spring
With these, a player simply had to purchase two boosters and shuffle them together to make a 40-card deck that could be played against someone else who had done the same thing