I like this idea Gian. I am not sure if this meets your need, but it would be great if Cardboard could just create some free form text field with a character limitation. It can say anything you want. For you, it might say "MVP." For others, they might use a different acronym or for an entirely different purpose. Just a thought as the feature you propose may have more of a broad purpose if we generalize the solution.

I like this idea. Perhaps to generalize a bit further, I could live with another free text box when you open the card (similar to the Estimate field). This field could be used to enter whatever free text the user wants to appear on the front of the card. Given the current card layout, this text could appear in the lower center of the card. Right now, I am using the Estimate field to indicate "MVP" or "P2" (Phase 2), etc. If there was another field in the card, we could go back to using the estimate field for its intended purpose.