At the beginning of your upkeep, look at the top card of your library. You may reveal that card. If an instant or sorcery card is revealed this way, transform Delver of Secrets.

Tap an untapped Merfolk you control: Target player mills a card.

When Kami of Terrible Secrets enters the battlefield, if you control an artifact and an enchantment, you draw a card and you gain 1 life.

Undergrowth — Search your library for a black card with mana value less than or equal to the number of creature cards in your graveyard, reveal it, put it into your hand, then shuffle.

Whenever a card is put into your graveyard from anywhere, you may put a quest counter on Quest for Ancient Secrets.

Remove five quest counters from Quest for Ancient Secrets and sacrifice it: Target player shuffles their graveyard into their library.

Whenever you cast a spell from your graveyard, draw a card.

Investigate. If this spell was cast from a graveyard, investigate twice instead. (Create a Clue token. It's an artifact with ", Sacrifice this artifact: Draw a card.")

Flashback

Whenever Stealer of Secrets deals combat damage to a player, draw a card.

Flying, ward

Council's dilemma — Whenever Tivit enters the battlefield or deals combat damage to a player, starting with you, each player votes for evidence or bribery. For each evidence vote, investigate. For each bribery vote, create a Treasure token.

While voting, you may vote an additional time. (The votes can be for different choices or for the same choice.)

Target opponent draws two cards, then you draw up to four cards. That opponent may repeat this process as many times as they choose.