As there is currently no way to make money other than grinding, I thought it would be cool if there was an 'Endless Mode'. In Endless Mode, there is an unbeatable AI (Level is selected by the player) where the amount of damage caused to it affects your reward in Electrum. Each level would have it's own multiplier. For example:
Level 3: Reward = Damage Dealt / 10
Level 4: Reward = Damage Dealt / 5
Level 5: Reward = Damage Dealt / 2
Let's say I dealt 400 damage to a level 3 before dying. I would get 40 Electrum from that. If I dealt 350 damage to a level 5 opponent, I would get 70. If I dealt 200 damage to a level 5, then my reward would be 100 Electrum.
This is only an idea, but I thought it would add a bit more for the high-end players to do.
Not entirely sure on how you could avoid running out of cards :/