Obeka, Brute Chronologist

{T}: The player whose turn it is may end the turn. (Exile all spells and abilities from the stack. The player whose turn it is discards down to their maximum hand size. Damage wears off, and "this turn" and "until end of turn" effects end.)

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.

Time Warp

Target player takes an extra turn after this one.

Last Chance

Take an extra turn after this one. At the beginning of that turn's end step, you lose the game.

Narset's Reversal

Copy target instant or sorcery spell, then return it to its owner's hand. You may choose new targets for the copy.

God-Eternal Kefnet

Flying
You may reveal the first card you draw each turn as you draw it. Whenever you reveal an instant or sorcery card this way, copy that card and you may cast the copy. That copy costs {2} less to cast.
When God-Eternal Kefnet dies or is put into exile from the battlefield, you may put it into its owner's library third from the top.

Brainstorm

Draw three cards, then put two cards from your hand on top of your library in any order.

Twiddle

You may tap or untap target artifact, creature, or land.

Isochron Scepter

Imprint — When this artifact enters, you may exile an instant card with mana value 2 or less from your hand.
{2}, {T}: You may copy the exiled card. If you do, you may cast the copy without paying its mana cost.

Elite Arcanist

When this creature enters, you may exile an instant card from your hand.
{X}, {T}: Copy the exiled card. You may cast the copy without paying its mana cost. X is the mana value of the exiled card.

Final Fortune

Sundial of the Infinite

{1}, {T}: End the turn. Activate only during your turn. (Exile all spells and abilities from the stack. Discard down to your maximum hand size. Damage wears off, and "this turn" and "until end of turn" effects end.)