Whenever Innocent Bystander is dealt 3 or more damage, investigate. (Create a Clue token. It's an artifact with ", Sacrifice this artifact: Draw a card.")

Soulbond (You may pair this creature with another unpaired creature when either enters. They remain paired for as long as you control both of them.)

As long as Tandem Lookout is paired with another creature, each of those creatures has "Whenever this creature deals damage to an opponent, draw a card."

Up to two target creatures you control each get +1/+0 until end of turn. They each deal damage equal to their power to another target creature, planeswalker, or battle.