Slumbering Dragon

Flying
Slumbering Dragon can't attack or block unless it has five or more +1/+1 counters on it.
Whenever a creature attacks you or a planeswalker you control, put a +1/+1 counter on Slumbering Dragon.

Gideon Jura

+2: During target opponent's next turn, creatures that player controls attack Gideon Jura if able.
−2: Destroy target tapped creature.
0: Until end of turn, Gideon Jura becomes a 6/6 Human Soldier creature that's still a planeswalker. Prevent all damage that would be dealt to him this turn.

Shipwreck Singer

Flying
{1}{U}: Target creature an opponent controls attacks this turn if able.
{1}{B}, {T}: Attacking creatures get -1/-1 until end of turn.

Batwing Brume

Prevent all combat damage that would be dealt this turn if {W} was spent to cast this spell. Each player loses 1 life for each attacking creature they control if {B} was spent to cast this spell. (Do both if {W}{B} was spent.)

Rowan Kenrith

+2: During target player's next turn, each creature that player controls attacks if able.
−2: Rowan Kenrith deals 3 damage to each tapped creature target player controls.
−8: Target player gets an emblem with "Whenever you activate an ability that isn't a mana ability, copy it. You may choose new targets for the copy."
Partner with Will Kenrith
Rowan Kenrith can be your commander.

Angler Turtle

Hexproof
Creatures your opponents control attack each combat if able.

Riddlekeeper

Whenever a creature attacks you or a planeswalker you control, that creature's controller mills two cards.

Respite

Prevent all combat damage that would be dealt this turn. You gain 1 life for each attacking creature.

Ever-Watching Threshold

Whenever an opponent attacks, if they attacked you and/or a planeswalker you control, draw a card.

Revenge of Ravens

Whenever a creature attacks you or a planeswalker you control, that creature's controller loses 1 life and you gain 1 life.

Patron of the Kitsune

Fox offering (You may cast this spell any time you could cast an instant by sacrificing a Fox and paying the difference in mana costs between this and the sacrificed Fox. Mana cost includes color.)
Whenever a creature attacks, you may gain 1 life.

Keep Watch

Orim's Prayer

Whenever one or more creatures attack you, you gain 1 life for each attacking creature.

Curse of the Nightly Hunt

Enchant player
Creatures enchanted player controls attack each combat if able.

Fumiko the Lowblood

Fumiko the Lowblood has bushido X, where X is the number of attacking creatures. (Whenever this creature blocks or becomes blocked, it gets +X/+X until end of turn.)
Creatures your opponents control attack each combat if able.

Bident of Thassa

Whenever a creature you control deals combat damage to a player, you may draw a card.
{1}{U}, {T}: Creatures your opponents control attack this turn if able.

Hissing Miasma

Whenever a creature attacks you, its controller loses 1 life.

Lightmine Field

Whenever one or more creatures attack, Lightmine Field deals damage to each of those creatures equal to the number of attacking creatures.