Wooded Foothills

{T}, Pay 1 life, Sacrifice Wooded Foothills: Search your library for a Mountain or Forest card, put it onto the battlefield, then shuffle.

Natural Order

As an additional cost to cast this spell, sacrifice a green creature.
Search your library for a green creature card, put it onto the battlefield, then shuffle.

Memnite

Crown of Flames

Enchant creature
{R}: Enchanted creature gets +1/+0 until end of turn.
{R}: Return Crown of Flames to its owner's hand.

Prosperous Innkeeper

When Prosperous Innkeeper enters the battlefield, create a Treasure token. (It's an artifact with "{T}, Sacrifice this artifact: Add one mana of any color.")
Whenever another creature enters the battlefield under your control, you gain 1 life.

Dragonspark Reactor

Whenever Dragonspark Reactor or another artifact enters the battlefield under your control, put a charge counter on Dragonspark Reactor.
{4}, Sacrifice Dragonspark Reactor: It deals damage equal to the number of charge counters on it to target player and that much damage to up to one target creature.

There and Back Again

(As this Saga enters and after your draw step, add a lore counter. Sacrifice after III.)
I — Up to one target creature can't block for as long as you control There and Back Again. The Ring tempts you.
II — Search your library for a Mountain card, put it onto the battlefield, then shuffle.
III — Create Smaug, a legendary 6/6 red Dragon creature token with flying, haste, and "When this creature dies, create fourteen Treasure tokens."

Mountain

Birds of Paradise

Great Furnace

Reckless Fireweaver

Whenever an artifact enters the battlefield under your control, Reckless Fireweaver deals 1 damage to each opponent.

Goldspan Dragon

Flying, haste
Whenever Goldspan Dragon attacks or becomes the target of a spell, create a Treasure token.
Treasures you control have "{T}, Sacrifice this artifact: Add two mana of any one color."

Tree of Tales

Vitu-Ghazi Guildmage

{4}{G}{W}: Create a 3/3 green Centaur creature token.
{2}{G}{W}: Populate. (Create a token that's a copy of a creature token you control.)

Season of Growth

Whenever a creature enters the battlefield under your control, scry 1. (Look at the top card of your library. You may put that card on the bottom of your library.)
Whenever you cast a spell that targets a creature you control, draw a card.

Third Path Iconoclast

Whenever you cast a noncreature spell, create a 1/1 colorless Soldier artifact creature token.

Taiga

Ingenious Artillerist

Whenever one or more artifacts enter the battlefield under your control, Ingenious Artillerist deals that much damage to each opponent.

Arcbound Crusher

Trample
Whenever another artifact enters the battlefield, put a +1/+1 counter on Arcbound Crusher.
Modular 1 (This creature enters the battlefield with a +1/+1 counter on it. When it dies, you may put its +1/+1 counters on target artifact creature.)

Whip Silk

Enchant creature
Enchanted creature has reach. (It can block creatures with flying.)
{G}: Return Whip Silk to its owner's hand.

Mox Opal

Metalcraft — {T}: Add one mana of any color. Activate only if you control three or more artifacts.