Blade of Selves

Equipped creature has myriad. (Whenever it attacks, for each opponent other than defending player, you may create a token copy that's tapped and attacking that player or a planeswalker they control. Exile the tokens at end of combat.)
Equip {4}

Enlightened Tutor

Search your library for an artifact or enchantment card, reveal it, then shuffle and put that card on top.

Vampiric Tutor

Search your library for a card, then shuffle and put that card on top. You lose 2 life.

Selesnya Signet

Sapphire Medallion

Blue spells you cast cost {1} less to cast.

Sol Ring

Demonic Tutor

Search your library for a card, put that card into your hand, then shuffle.

Commander's Sphere

{T}: Add one mana of any color in your commander's color identity.
Sacrifice Commander's Sphere: Draw a card.

Flaming Fist

Commander creatures you own have "Whenever this creature attacks, it gains double strike until end of turn."

Golgari Signet

Rhythm of the Wild

Creature spells you control can't be countered.
Nontoken creatures you control have riot. (They enter with your choice of a +1/+1 counter or haste.)

Ruby Medallion

Red spells you cast cost {1} less to cast.

Orzhov Signet

Finest Hour

Exalted (Whenever a creature you control attacks alone, that creature gets +1/+1 until end of turn.)
Whenever a creature you control attacks alone, if it's the first combat phase of the turn, untap that creature. After this phase, there is an additional combat phase.

Emerald Medallion

Green spells you cast cost {1} less to cast.

Worldly Tutor

Search your library for a creature card, reveal it, then shuffle and put the card on top.

Snow-Covered Swamp

Snow-Covered Island

Pearl Medallion

White spells you cast cost {1} less to cast.

Idyllic Tutor

Search your library for an enchantment card, reveal it, put it into your hand, then shuffle.

Snow-Covered Forest

Gruul Signet

Jet Medallion

Black spells you cast cost {1} less to cast.

Brave the Sands

Creatures you control have vigilance.
Each creature you control can block an additional creature each combat.

Fist of Suns

You may pay {W}{U}{B}{R}{G} rather than pay the mana cost for spells you cast.

Snow-Covered Mountain

Simic Signet

Arcane Signet

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

Boros Signet

Dream Halls

Rather than pay the mana cost for a spell, its controller may discard a card that shares a color with that spell.

Have

Progenitus

Protection from everything
If Progenitus would be put into a graveyard from anywhere, reveal Progenitus and shuffle it into its owner's library instead.

Rakdos Signet

Izzet Signet

Command Tower

Snow-Covered Plains

Profane Tutor

Suspend 2—{1}{B} (Rather than cast this card from your hand, pay {1}{B} and exile it with two time counters on it. At the beginning of your upkeep, remove a time counter. When the last is removed, you may cast it without paying its mana cost.)
Search your library for a card, put that card into your hand, then shuffle.

Dimir Signet

Azorius Signet

Semblance Anvil

Imprint — When Semblance Anvil enters, you may exile a nonland card from your hand.
Spells you cast that share a card type with the exiled card cost {2} less to cast.