Plains

Kor Skyfisher

Flying
When Kor Skyfisher enters, return a permanent you control to its owner's hand.

Palace Jailer

When Palace Jailer enters, you become the monarch.
When Palace Jailer enters, exile target creature an opponent controls until an opponent becomes the monarch.

Militia Bugler

Vigilance (Attacking doesn't cause this creature to tap.)
When Militia Bugler enters, look at the top four cards of your library. You may reveal a creature card with power 2 or less from among them and put it into your hand. Put the rest on the bottom of your library in a random order.

Anafenza, Kin-Tree Spirit

Whenever another nontoken creature you control enters, bolster 1. (Choose a creature with the least toughness among creatures you control and put a +1/+1 counter on it.)

Scepter of Empires

{T}: Scepter of Empires deals 1 damage to target player or planeswalker. It deals 3 damage instead if you control artifacts named Crown of Empires and Throne of Empires.

Cenn's Tactician

{W}, {T}: Put a +1/+1 counter on target Soldier creature.
Each creature you control with a +1/+1 counter on it can block an additional creature each combat.

Noble Templar

Vigilance
Plainscycling {2} ({2}, Discard this card: Search your library for a Plains card, reveal it, put it into your hand, then shuffle.)

Unexpectedly Absent

Put target nonland permanent into its owner's library just beneath the top X cards of that library.

Enlistment Officer

First strike
When Enlistment Officer enters, reveal the top four cards of your library. Put all Soldier cards revealed this way into your hand and the rest on the bottom of your library in any order.

Crown of Empires

{3}, {T}: Tap target creature. Gain control of that creature instead if you control artifacts named Scepter of Empires and Throne of Empires.

Throne of Empires

{1}, {T}: Create a 1/1 white Soldier creature token. Create five of those tokens instead if you control artifacts named Crown of Empires and Scepter of Empires.

Thraben Inspector

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

Aerial Responder

Idyllic Grange

({T}: Add {W}.)
Idyllic Grange enters tapped unless you control three or more other Plains.
When Idyllic Grange enters untapped, put a +1/+1 counter on target creature you control.

Karoo

Karoo enters tapped.
When Karoo enters, sacrifice it unless you return an untapped Plains you control to its owner's hand.
{T}: Add {C}{W}.