XMage
Magic Another Game Engine
...It supports single matches and tournaments with dozens game modes like duel, multiplayer, standard, modern, commander, pauper, oathbreaker, historic, freeform and much more. Local server supports a special test mode for testing combos and other game situations with pre-defined conditions. There are public servers where you can play XMage against other players. You can also host your own server to play against the AI and/or your friends. Supports special formats like Commander (up to 10 players), Oathbreaker, Cube, Tiny Leaders, Super Standard, Historic Standard and more.