Sol Ring

Liliana's Steward

{T}, Sacrifice Liliana's Steward: Target opponent discards a card. Activate only as a sorcery.

Burglar Rat

When this creature enters, each opponent discards a card.

Tinybones, Bauble Burglar

Whenever an opponent discards a card, exile it from their graveyard with a stash counter on it.
During your turn, you may play cards you don't own with stash counters on them from exile, and mana of any type can be spent to cast those spells.
{3}{B}, {T}: Each opponent discards a card. Activate only as a sorcery.