Whenever you cast a historic spell, investigate. This ability triggers only once each turn. (Artifacts, legendaries, and Sagas are historic. To investigate, create a Clue token. It's an artifact with "{2}, Sacrifice this artifact: Draw a card.") Doctor's companion (You can have two commanders if the other is the Doctor.)

Flying Whenever a nontoken creature you control dies, investigate. Clues you control have exalted. (Whenever a creature you control attacks alone, that creature gets +1/+1 until end of turn for each instance of exalted among permanents you control.)

You have no maximum hand size. At the beginning of your upkeep, investigate. (Create a Clue token. It's an artifact with "{2}, Sacrifice this artifact: Draw a card.") Whenever you draw your second card each turn, put two +1/+1 counters on Morska, Undersea Sleuth.

Ward {2} At the beginning of each combat, other Clues you control become 6/6 Plant creatures in addition to their other types until end of turn. {2}, Sacrifice Tangletrove Kelp: Draw a card.