Frontier Warmonger

Whenever one or more creatures attack one of your opponents or a planeswalker they control, those creatures gain menace until end of turn.

Invasion Plans

All creatures block each combat if able.
The attacking player chooses how each creature blocks each combat.

Sphere of Safety

Creatures can't attack you or planeswalkers you control unless their controller pays {X} for each of those creatures, where X is the number of enchantments you control.

Sol Ring

Baird, Steward of Argive

Vigilance
Creatures can't attack you or planeswalkers you control unless their controller pays {1} for each of those creatures.

Arcane Signet

{T}: Add one mana of any color in your commander's color identity.

Fellwar Stone

{T}: Add one mana of any color that a land an opponent controls could produce.

Fire Diamond

Fire Diamond enters tapped.
{T}: Add {R}.

Marble Diamond

Marble Diamond enters tapped.
{T}: Add {W}.

Kazuul, Tyrant of the Cliffs

Whenever a creature an opponent controls attacks, if you're the defending player, create a 3/3 red Ogre creature token unless that creature's controller pays {3}.

Basandra, Battle Seraph

Flying
Players can't cast spells during combat.
{R}: Target creature attacks this turn if able.

Search the Premises

Whenever a creature attacks you or a planeswalker you control, investigate. (Create a Clue token. It's an artifact with "{2}, Sacrifice this artifact: Draw a card.")

Star Compass

Star Compass enters tapped.
{T}: Add one mana of any color that a basic land you control could produce.