Jumpstart: Historic Horizons is a gargantuan set and new way to play the game that’s being added into MTG Arena later this week, after a short delay.
You also had sets like Modern Horizons, which weren’t brought into the digital client either. You had Commander decks - which could, theoretically, be introduced into Historic without completely breaking things open - that were never added. However, while we all waited for that, more and more disparities started appearing between paper MTG and Arena. Nobody was expecting it to be a thing that happened any time soon, but it was broadly understood that was what players wanted. While the app started off only offering the Standard format, as sets rotated out it birthed Historic - which a lot of people assumed would lead to it eventually adding in the likes of Pioneer, Modern and so on. It’s no secret that MTG isn’t exactly cheap, but Arena being free-to-play - albeit with a fairly substandard in-game economy - means lots of people can enjoy a paper experience without the price tag. MTG Arena always felt like a way to capture the wonders of paper Magic: The Gathering in a way that was more approachable, available no matter where you were and affordable.