Insidious Roots

Creature tokens you control have "{T}: Add one mana of any color."
Whenever one or more creature cards leave your graveyard, create a 0/1 green Plant creature token, then put a +1/+1 counter on each Plant you control.

Perpetual Timepiece

{T}: Mill two cards.
{2}, Exile Perpetual Timepiece: Shuffle any number of target cards from your graveyard into your library.

Deranged Assistant

{T}, Mill a card: Add {C}. (To mill a card, put the top card of your library into your graveyard.)

Skull Prophet

{T}: Add {B} or {G}.
{T}: Mill two cards.

Sol Ring

Millikin

Arcane Signet

{T}: Add one mana of any color in your commander's color identity.

Sidisi, Brood Tyrant

Whenever Sidisi, Brood Tyrant enters the battlefield or attacks, mill three cards.
Whenever one or more creature cards are put into your graveyard from your library, create a 2/2 black Zombie creature token.