Consider

T: Search your library for a legendary card, reveal that card, put it into your hand, then shuffle.

Roku's Mastery deals X damage to target creature. If X is 4 or more, scry 2. (Look at the top two cards of your library, then put any number of them on the bottom and the rest on top in any order.)

T: Destroy target creature of your choice, then destroy target creature of an opponent's choice. Activate only during your turn, before attackers are declared.

When this enchantment enters, create a 1/1 white Human Soldier creature token. Whenever a creature you control dies, each opponent loses 1 life and you gain 1 life.

1, Sacrifice this creature: Destroy target artifact or enchantment.

If you control a commander, you may cast this spell without paying its mana cost. Creatures you control gain indestructible until end of turn.

Draw a card. If a graveyard has twenty or more cards in it, draw three cards instead.