[Update #2]: The Alchemy: Dominaria mini-expansion has now arrived with 30 new cards and Historic 'unrebalances.'
[Update]: MTG Arena will be getting Shadows over Innistrad Remastered in 2023 and a second Explorer Anthology in 2022.
Continuing with the recent tradition of releasing a smaller, Alchemy focused expansion a short while after a Standard set, MTG Arena will be unleashing Alchemy: Dominaria on October 6th. This mini-expansion will bring with it 30 new cards to play around with, most of which designed to complement the recent sets and hopefully give relevance to some of the underdeveloped mechanics like Enlist and Vehicles.
The full list of cards has not been revealed just yet, and most likely won't be until Alchemy: Dominaria is nearly ready to launch, but there is one card in specific I would like to highlight - Oracle of the Alpha. Pictured below, it's a 3-mana creature that conjures and shuffles the entire Power 9 into your library!
For those of you that might not know, the Power 9 is a collection of some of the most powerful (and old) cards in Magic, all of which are banned or restricted in a majority of formats. This list includes numerous mana accelerators like Mox Ruby, as well as spicy blue spells like Ancestral Recall and Time Walk. And soon you'll be able to mess around with them in MTG Arena!
Naturally, there is a big difference between starting on turn 1 with a Mox Ruby in your hand and drawing it on turn 15. Similarly, Time Walk is an absurdly powerful spell, but you can't exactly plan your deck around it when it's simply one card hidden somewhere in your freshly enlarged library. So as much as these cards are overpowered in a vacuum, I highly doubt that Oracle of the Alpha will be.
Instead, I expect Oracle of the Alpha to be more of a combo piece rather than a standalone powerhouse. You play it on turn 3, tutor for Time Walk at some point in the future once the opponent is shields down, and then immediately play it in an effort to start chaining extra turns until you win. There's a fair few hoops you'll need to jump through in order to get there, but it's not every day you'll get a chance to style on your opponents with endless Time Walks!
Once Oracle of the Alpha and its accompanying Alchemy: Dominaria set arrive on October 6th I'll make sure to let you know. Until then, you can keep track of previews and teasers over at the MTG website. Enjoy!