Actually, all cards have gradients, but they are more subtle since they are from Red to Brighter Red for example.
I kinda missed the opportunity to make the Ray of Light more punchy with a gradient as well.
Of course Death Touch has its own double colour gradient (didn't feel like trying to make a whole new Shadow Element in the last hours was worth it)
Now Brain Wipe would have been better with a little bit more. I just couldn't find out what