Plains

Mountain

Annex Sentry

Toxic 1 (Players dealt combat damage by this creature also get a poison counter.)
When Annex Sentry enters the battlefield, exile target artifact or creature an opponent controls with mana value 3 or less until Annex Sentry leaves the battlefield.

Sundown Pass

Sundown Pass enters the battlefield tapped unless you control two or more other lands.
{T}: Add {R} or {W}.

Anim Pakal, Thousandth Moon

Whenever you attack with one or more non-Gnome creatures, put a +1/+1 counter on Anim Pakal, then create X 1/1 colorless Gnome artifact creature tokens that are tapped and attacking, where X is the number of +1/+1 counters on Anim Pakal.

Battlefield Forge

{T}: Add {C}.
{T}: Add {R} or {W}. Battlefield Forge deals 1 damage to you.

Novice Inspector

When Novice Inspector enters the battlefield, investigate. (Create a Clue token. It's an artifact with "{2}, Sacrifice this artifact: Draw a card.")

Recommission

Return target artifact or creature card with mana value 3 or less from your graveyard to the battlefield. If a creature enters the battlefield this way, it enters with an additional +1/+1 counter on it.

Warleader's Call

Creatures you control get +1/+1.
Whenever a creature enters the battlefield under your control, Warleader's Call deals 1 damage to each opponent.

Demand Answers

As an additional cost to cast this spell, sacrifice an artifact or discard a card.
Draw two cards.

Experimental Synthesizer

When Experimental Synthesizer enters or leaves the battlefield, exile the top card of your library. Until end of turn, you may play that card.
{2}{R}, Sacrifice Experimental Synthesizer: Create a 2/2 white Samurai creature token with vigilance. Activate only as a sorcery.

Dusk Rose Reliquary

As an additional cost to cast this spell, sacrifice an artifact or creature.
Ward {2}
When Dusk Rose Reliquary enters the battlefield, exile target artifact or creature an opponent controls until Dusk Rose Reliquary leaves the battlefield.

Sokenzan, Crucible of Defiance

{T}: Add {R}.
Channel — {3}{R}, Discard Sokenzan, Crucible of Defiance: Create two 1/1 colorless Spirit creature tokens. They gain haste until end of turn. This ability costs {1} less to activate for each legendary creature you control.

Citizen's Crowbar

When Citizen's Crowbar enters the battlefield, create a 1/1 green and white Citizen creature token, then attach Citizen's Crowbar to it.
Equipped creature gets +1/+1 and has "{W}, {T}, Sacrifice Citizen's Crowbar: Destroy target artifact or enchantment."
Equip {2} ({2}: Attach to target creature you control. Equip only as a sorcery.)

Kayla's Reconstruction

Look at the top seven cards of your library. Put up to X artifact and/or creature cards with mana value 3 or less from among them onto the battlefield. Put the rest on the bottom of your library in a random order.

Gleeful Demolition

Destroy target artifact. If you controlled that artifact, create three 1/1 red Phyrexian Goblin creature tokens.

Voldaren Epicure

When Voldaren Epicure enters the battlefield, it deals 1 damage to each opponent. Create a Blood token. (It's an artifact with "{1}, {T}, Discard a card, Sacrifice this artifact: Draw a card.")