+3/+1 doesnt hurt, either
Colfenor is an entirely passive engine that brings a small creature from your graveyard to your hand, one that you can cast for one mana and immediately sac to Krark-Clan Ironworks or Ashnod's Altar
While Planetarium does get stronger when you add other Scry and Surveil effects to your deck, because of the artifacts activated ability, you dont even need to build around it for it to pull its weight
(A regular Art card can be found in 30% of packs and a foil-stamped Signature Art card can be found in 5% of packs.) Every pack Includes 1-4 cards of rarity Rare or higher and 3-6 Uncommon, 6-9 Common, and 1 Land cards
Its not that effective of a lord since its a 6-drop, but its a combo engine, a stax piece, and a recursion effect all in one, so its hard not to get your manas worth with Mikaeus
Why Wizards of the Coast believed that having multiple colors was an upside to a creature back then, Ill never understand (hello