MTGATracker for macOS has entered beta! Go check it out on the MTGATracker Releases page!
Note that this is a very early version; there are likely many features that may not work at all currently. For example, the 6.2.0 beta version of MTGATracker does not auto-update (so you will have to come back regularly and install updates manually).
Also, a note from Spencatro: MTGATracker is looking for open-source developers to volunteer to maintain MTGATracker! This would include things like testing and approving new pull requests, or even writing code for MTGATracker developer directly. Bonus points if you can develop for or test on macOS! (My super old macbook can’t quite handle Arena, so testing is pretty difficult for me :P ) If you’re interested, please send me a note at [email protected] !