Theres plenty of discussion on whether the card should be banned in Modern given that it already is in Legacy, as it encourages narrow deckbuilding
Ad Nauseum and Underworld Breach can certainly help get the job done, but the easiest and most efficient way to win the game with Thassas Oracle is to use Demonic consultation
Its value on value on value, and easily one of the best Elf cards that has been printed in a good long while
We can add Blood CryptBlood Crypt, Steam VentsSteam Vents and Watery GraveWatery Grave, then work through the crowd lands such as Training CenterTraining Center, Luxury SuiteLuxury Suite and Morphic PoolMorphic Pool so that you can get a more varied mana base
Karakas would work on offense and defense in EDH, saving your own commander and stealing lots of tempo from opponents
Even if your opponent tries to use removal spells to get rid of Arasta, youre still creating tokens and dealing damage