The Magic Bandit

Whenever a player casts a spell they don't own, that player creates a Treasure token.

Whenever a creature deals combat damage to one of your opponents, its controller looks at the top card of that opponent's library and exiles it face down. They may play that card for as long as it remains exiled. Mana of any type can be spent to cast a spell this way.

Flying, deathtouch

Whenever you cast your first spell during each opponent's turn, look at the top card of that player's library, then exile it face down. You may play that card for as long as it remains exiled, and mana of any type can be spent to cast it.

Spells you cast but don't own cost less to cast.

Whenever one or more creatures you control deal combat damage to a player, look at the top card of that player's library, then exile it face down. You may play that card for as long as it remains exiled, and mana of any type can be spent to cast that spell.

Deathtouch

When Gonti enters, look at the top four cards of target opponent's library, exile one of them face down, then put the rest on the bottom of that library in a random order. You may cast that card for as long as it remains exiled, and mana of any type can be spent to cast that spell.

Whenever you attack, target creature gains deathtouch until end of turn.

Whenever one or more creatures you control deal combat damage to a player, create a Treasure token, then look at the top card of that player's library and exile it face down. You may cast that card for as long as it remains exiled. (A Treasure token is an artifact with ", Sacrifice this token: Add one mana of any color.")

Flying

Whenever this creature deals combat damage to a player, look at the top three cards of that player's library, exile one of them face down, then put the rest into their graveyard. You may cast that card for as long as it remains exiled, and mana of any type can be spent to cast that spell.