At the beginning of your end step, you may exile target creature you control, then return that card to the battlefield under your control.

Whenever you cast an artifact spell, investigate. (Create a Clue token. It's an artifact with "{2}, Sacrifice this token: Draw a card.") Activated abilities of artifacts you control cost {1} less to activate. This effect can't reduce the mana in that cost to less than one mana.

Nonartifact spells you cast have improvise. (Your artifacts can help cast those spells. Each artifact you tap after you're done activating mana abilities pays for {1}.)

Whenever another nontoken creature you control enters, investigate. {T}, Sacrifice X Clues: Target opponent reveals the top X cards of their library. You may put a nonland permanent card with mana value X or less from among them onto the battlefield under your control. That player puts the rest on the bottom of their library in a random order.

Woman Who Walked the Earth — When Martha Jones enters, investigate. (Create a Clue token. It's an artifact with "{2}, Sacrifice this token: Draw a card.") Whenever you sacrifice a Clue, Martha Jones and up to one other target creature can't be blocked this turn. Doctor's companion (You can have two commanders if the other is the Doctor.)

This spell costs {W}{U} more to cast for each target beyond the first. Choose any number of target players. Investigate X times, where X is the total number of creatures those players control.

Target noncreature artifact you control becomes a 0/0 artifact creature. Put four +1/+1 counters on each artifact that became a creature this way. Overload {4}{U}{U} (You may cast this spell for its overload cost. If you do, change "target" in its text to "each.")

For each token you control, create a token that's a copy of that permanent.