When Boareskyr Tollkeeper enters, target opponent reveals all creature and land cards in their hand. Choose one of them. That card perpetually gains "This permanent enters tapped."

Backup 1
Whenever this creature attacks, tap target artifact or creature an opponent controls.

Kicker
Creatures you control get +1/+1 until end of turn. If this spell was kicked, instead creatures you control get +2/+2 and gain first strike until end of turn.

Tap all creatures your opponents control. Creatures you control gain lifelink until end of turn.

Enchant creature
Enchanted creature gets +2/+2 as long as it's a Human. Otherwise, it can't attack or block.

Sliver creatures you control have double strike.

Put a shield counter on target creature.
Scry 1.

Constellation — Whenever this enchantment or another enchantment you control enters, put a blessing counter on this enchantment.
Creatures you control get +1/+1 for each blessing counter on this enchantment.

If you would gain life, you gain twice that much life instead.

Backup 1
Flying, first strike, lifelink

When this creature enters, you may search your graveyard, hand, and/or library for an Aura card and put it onto the battlefield attached to this creature. If you search your library this way, shuffle.

Flying
: This creature gains first strike until end of turn. ( can be paid with one mana from a snow permanent.)

Flying
When this creature leaves the battlefield, choose an opponent who controls more lands than you. Search your library for a number of Plains cards equal to the difference, reveal those cards, put one of them onto the battlefield tapped and the rest into your hand, then shuffle.

Create two 1/1 colorless Borg artifact creature tokens, then artifact creatures you control gain protection from the color of your choice until end of turn.

Enchant artifact or creature
As long as enchanted permanent is a creature, it gets +1/+1 for each creature and/or Vehicle you control.
Channel — , Discard this card: Create two 1/1 colorless Pilot creature tokens with "This token crews Vehicles as though its power were 2 greater."

Vigilance
Whenever an opponent casts a spell, if no mana was spent to cast it, counter that spell.
Sacrifice Boromir: Creatures you control gain indestructible until end of turn. The Ring tempts you.

Battalion — Whenever this creature and at least two other creatures attack, this creature gets +2/+2 until end of turn.

Prevent all combat damage that would be dealt by target attacking or blocking creature this turn. If was spent to cast this spell, Boros Fury-Shield deals damage to that creature's controller equal to the creature's power.

Battalion — Whenever this creature and at least two other creatures attack, this creature gains lifelink until end of turn.

Create two 3/2 white Hero creature tokens with vigilance.
Basic landcycling

Escalate
Choose one or both —
• Creatures you control get +2/+0 until end of turn.
• Creatures you control get +0/+2 until end of turn.

When this enchantment enters, exile target nonland permanent an opponent controls until this enchantment leaves the battlefield.

Whenever you cast a spell, you may gain ½ life for each word in that spell's name.

This creature enters with a number of +1/+1 counters on it equal to one plus the number of other creatures you control.
Alliance — Whenever another creature you control enters, put a +1/+1 counter on this creature.
When this creature dies, create a 1/1 green and white Citizen creature token for each +1/+1 counter on it.

Enchant creature
Enchanted creature can't attack, block, or transform.
Sacrifice another permanent: Attach this Aura to target creature. Activate only as a sorcery and only once each turn.

Enchant permanent
Enchanted permanent can't attack, block, or crew Vehicles, and its activated abilities can't be activated unless they're mana abilities.

Enchant creature
Enchanted creature can't attack or block.