Song of Totentanz

Create X 1/1 black Rat creature tokens with "This creature can't block." Creatures you control gain haste until end of turn.

Magnus the Red

Flying
Unearthly Power — Instant and sorcery spells you cast cost {1} less to cast for each creature token you control.
Blade of Magnus — Whenever Magnus the Red deals combat damage to a player, create a 3/3 red Spawn creature token.

Omniscience

You may cast spells from your hand without paying their mana costs.

Thousand-Year Storm

Whenever you cast an instant or sorcery spell, copy it for each other instant and sorcery spell you've cast before it this turn. You may choose new targets for the copies.

Rise of the Eldrazi

This spell can't be countered.
Destroy target permanent. Target player draws four cards. Take an extra turn after this one.
Exile Rise of the Eldrazi.

Twinning Staff

If you would copy a spell one or more times, instead copy it that many times plus an additional time. You may choose new targets for the additional copy.
{7}, {T}: Copy target instant or sorcery spell you control. You may choose new targets for the copy.