Inventors' Fair

At the beginning of your upkeep, if you control three or more artifacts, you gain 1 life.
{T}: Add {C}.
{4}, {T}, Sacrifice Inventors' Fair: Search your library for an artifact card, reveal it, put it into your hand, then shuffle. Activate only if you control three or more artifacts.

Font of Mythos

At the beginning of each player's draw step, that player draws two additional cards.

Lotus Petal

{T}, Sacrifice Lotus Petal: Add one mana of any color.

Blast Zone

Blast Zone enters with a charge counter on it.
{T}: Add {C}.
{X}{X}, {T}: Put X charge counters on Blast Zone.
{3}, {T}, Sacrifice Blast Zone: Destroy each nonland permanent with mana value equal to the number of charge counters on Blast Zone.

Memnite

Ancient Tomb

{T}: Add {C}{C}. Ancient Tomb deals 2 damage to you.

Howling Golem

Whenever Howling Golem attacks or blocks, each player draws a card.

Temple Bell

Urza's Saga

(As this Saga enters and after your draw step, add a lore counter. Sacrifice after III.)
I — Urza's Saga gains "{T}: Add {C}."
II — Urza's Saga gains "{2}, {T}: Create a 0/0 colorless Construct artifact creature token with 'This creature gets +1/+1 for each artifact you control.'"
III — Search your library for an artifact card with mana cost {0} or {1}, put it onto the battlefield, then shuffle.

Ashnod's Altar

Black Vise

As Black Vise enters, choose an opponent.
At the beginning of the chosen player's upkeep, Black Vise deals X damage to that player, where X is the number of cards in their hand minus 4.

Reliquary Tower

You have no maximum hand size.
{T}: Add {C}.

Ornithopter

Howling Mine

At the beginning of each player's draw step, if Howling Mine is untapped, that player draws an additional card.