Havi has indestructible as long as there are four or more historic cards in your graveyard. (Artifacts, legendaries, and Sagas are historic.)
Sage Project — Whenever Havi or another legendary creature you control dies, return target legendary creature card with lesser mana value from your graveyard to the battlefield tapped.

, : Exile target card from a graveyard.
, , Sacrifice this artifact: Exile target nonland card from a graveyard, all other cards from graveyards with the same name as that card, and all permanents with that name.

: Put a +1/+1 counter on each artifact creature you control.

Enchant creature
Enchanted creature gets +3/+3.
Dredge 2 (If you would draw a card, you may mill two cards instead. If you do, return this card from your graveyard to your hand.)

This artifact enters tapped.
, , Sacrifice this artifact: Target player loses the game.

Meet in Reverse — You draw cards from the bottom of your library rather than the top.
Spoilers — Whenever an opponent scries, surveils, or searches their library, put a +1/+1 counter on River Song. Then River Song deals damage to that player equal to its power.

When this creature enters, choose up to one —
• Destroy target artifact an opponent controls.
• This creature fights target Zombie an opponent controls.

Destroy all artifacts, then Structural Assault deals damage to each creature equal to the number of artifacts that were put into graveyards from the battlefield this turn.

, Discard a card: Draw a card.

Return up to three target land cards from your graveyard to the battlefield tapped. Create that many 4/2 green Plant Warrior creature tokens with reach.
Flashback (You may cast this card from your graveyard for its flashback cost. Then exile it.)

When this creature enters, flip it from a height of at least one foot. Sacrifice this creature unless it turns over completely at least once during the flip and lands face up.

Whenever this creature or another creature or artifact you control dies, target opponent loses 1 life and you gain 1 life.

When this creature enters, you and target opponent each draw a card.

Whenever a Beast enters, you may gain 3 life.

Graft 2 (This creature enters with two +1/+1 counters on it. Whenever another creature enters, you may move a +1/+1 counter from this creature onto it.)
: Target creature with a +1/+1 counter on it gains reach until end of turn. (It can block creatures with flying.)

Flying
You may exert this creature as it attacks. When you do, creatures you control get +1/+1 until end of turn. (An exerted creature won't untap during your next untap step.)

: Add .
, : Add , , or .

Defender (This creature can't attack.)
When this creature enters, target player mills four cards. (They put the top four cards of their library into their graveyard.)

Fear (This creature can't be blocked except by artifact creatures and/or black creatures.)
Sacrifice a creature: Regenerate this creature.
Transmute (, Discard this card: Search your library for a card with the same mana value as this card, reveal it, put it into your hand, then shuffle. Transmute only as a sorcery.)

Exile target enchantment.
Cycling (, Discard this card: Draw a card.)