I'm actually working on this right now! https://chiplis.com/ironsmith

It's a parser + (de)compiler and rules engine which I'm trying to get to 100% coverage over all Standard/Modern/Vintage/Commander legal cards. About 23000 of them are partially supported, while 15k currently work in full (~3k more than what MTGA currently supports, IIRC). It also allows for P2P 4-way multiplayer which Arena unfortunately does not :/