Matari, Ambitious Collector

Ward - Discard a card
Whenever an opponent discards a card, gain 1 life
and exile it. You may cast that card for as long as
it remains exiled, and mana of any type can be
spent to cast it. After the game ends, keep each
card you played this way.
{1}{w/b}{w/b}, {t}: Target player reveals their hand. You choose a nonland card from it. That player
discards that card.