Keen-Eared Sentry

You have hexproof. (You can't be the target of spells or abilities your opponents control.)
Each opponent can't venture into the dungeon more than once each turn.

Loyal Warhound

Vigilance
When Loyal Warhound enters, if an opponent controls more lands than you, search your library for a basic Plains card, put it onto the battlefield tapped, then shuffle.

Cave of the Frost Dragon

If you control two or more other lands, Cave of the Frost Dragon enters tapped.
{T}: Add {W}.
{4}{W}: Cave of the Frost Dragon becomes a 3/4 white Dragon creature with flying until end of turn. It's still a land.

Grand Master of Flowers

As long as Grand Master of Flowers has seven or more loyalty counters on him, he's a 7/7 Dragon God creature with flying and indestructible.
+1: Target creature without first strike, double strike, or vigilance can't attack or block until your next turn.
+1: Search your library and/or graveyard for a card named Monk of the Open Hand, reveal it, and put it into your hand. If you search your library this way, shuffle.

Icingdeath, Frost Tyrant

Flying, vigilance
When Icingdeath, Frost Tyrant dies, create Icingdeath, Frost Tongue, a legendary white Equipment artifact token with "Equipped creature gets +2/+0," "Whenever equipped creature attacks, tap target creature defending player controls," and equip {2}.

Priest of Ancient Lore

When Priest of Ancient Lore enters, you gain 1 life and draw a card.

Paladin Class

(Gain the next level as a sorcery to add its ability.)
Spells your opponents cast during your turn cost {1} more to cast.
{2}{W}: Level 2
Creatures you control get +1/+1.
{4}{W}: Level 3
Whenever you attack, until end of turn, target attacking creature gets +1/+1 for each other attacking creature and gains double strike.

Guardian of Faith

Flash
Vigilance
When Guardian of Faith enters, any number of other target creatures you control phase out. (Treat them and anything attached to them as though they don't exist until their controller's next turn.)

Plains

Nadaar, Selfless Paladin

Vigilance
Whenever Nadaar, Selfless Paladin enters or attacks, venture into the dungeon. (Enter the first room or advance to the next room.)
Other creatures you control get +1/+1 as long as you've completed a dungeon.

Dawnbringer Cleric

When Dawnbringer Cleric enters, choose one —
• Cure Wounds — You gain 2 life.
• Dispel Magic — Destroy target enchantment.
• Gentle Repose — Exile target card from a graveyard.

Portable Hole

When Portable Hole enters, exile target nonland permanent an opponent controls with mana value 2 or less until Portable Hole leaves the battlefield.

Divine Smite

Target creature or planeswalker an opponent controls phases out. If that permanent is black, exile it instead. (If it phases out, treat it and anything attached to it as though they don't exist until its controller's next turn.)

Dancing Sword

Equipped creature gets +2/+1.
When equipped creature dies, you may have Dancing Sword become a 2/1 Construct artifact creature with flying and ward {1}. If you do, it isn't an Equipment.
Equip {1}

Leather Armor

Equipped creature gets +0/+1 and has ward {1}. (Whenever equipped creature becomes the target of a spell or ability an opponent controls, counter it unless that player pays {1}.)
Equip {0}. Activate only once each turn.

Steadfast Paladin

Monk of the Open Hand

Flurry of Blows — Whenever you cast your second spell each turn, put a +1/+1 counter on Monk of the Open Hand.