Its already a very popular card game, and could be one of the best trading card games out there in the coming years!
But you do want to avoid the three common ways custom cards get ruined: Use high-quality art Bigger is better
For example, if your opponent passes the turn with two black mana available, there's a good chance they have a copy of Heartless Act at the ready
For those of you who don't remember, Starter Decks were the original "entry level" type of sealed offering, These decks had sixty cards and included enough basic lands to make a rudimentary deck
In Onslaught block, we started making cycling cards that had an effect when cycled
When the evoke elementals were spoiled in Modern Horizons 2, people waxed lyrical about how broken Grief with Ephemerate was going to be, but in practice that interaction did not make any material impact on the format, and instead its been more commonly combined with Fury and Solitude in the Four-Colour Yorion, Sky Nomad decks