2 cards where the text includes “were mana” and the set is “ths”

Daxos of Meletis (Theros #191)

Daxos of Meletis {1}{W}{U}

Legendary Creature — Human Soldier

Daxos of Meletis can’t be blocked by creatures with power 3 or greater.

Whenever Daxos of Meletis deals combat damage to a player, exile the top card of that player’s library. You gain life equal to that card’s mana value. Until end of turn, you may cast that card and you may spend mana as though it were mana of any color to cast that spell.

2/2

Illustrated by Karla Ortiz

Standard
Alchemy
Pioneer
Explorer
Modern
Historic
Legacy
Brawl
Vintage
Timeless
Commander
Pauper
Oathbreaker
Penny
Psychic Intrusion (Theros #200)

Psychic Intrusion {3}{U}{B}

Sorcery

Target opponent reveals their hand. You choose a nonland card from that player’s graveyard or hand and exile it. You may cast that card for as long as it remains exiled, and you may spend mana as though it were mana of any color to cast that spell.

Illustrated by Jaime Jones

Standard
Alchemy
Pioneer
Explorer
Modern
Historic
Legacy
Brawl
Vintage
Timeless
Commander
Pauper
Oathbreaker
Penny

It is the moment of discovery, the triumph of the mind, and the end of these results.