@lizardsquid I can absolutely recommend Faeria; 'tis what I play now to scratch the M:tG itch! Free-to-play with astoundingly little pay-to-win or profiteering; runs on Linux and Android; fairly deep tactically*; cute, polished artwork; pleasant worldbuilding that supports but doesn't intrude upon gameplay; healthy online metagame..
*It's not quite M:tG, I think - but way, way more depth than Hearthstone et. al..