Sol Ring

Relentless Assault

Untap all creatures that attacked this turn. After this main phase, there is an additional combat phase followed by an additional main phase.

Beacon of Tomorrows

Target player takes an extra turn after this one. Shuffle Beacon of Tomorrows into its owner's library.

Seize the Day

Untap target creature. After this main phase, there is an additional combat phase followed by an additional main phase.
Flashback {2}{R} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Narset, Enlightened Master

First strike, hexproof
Whenever Narset attacks, exile the top four cards of your library. Until end of turn, you may cast noncreature spells from among those cards without paying their mana costs.

Long-Term Plans

Search your library for a card, then shuffle and put that card third from the top.