Board overlays

This is a new concept we are working on. It will allow displaying color heatmaps or text based annotations on top of item cards in Kanban/Gantt/List based on their properties/metrics.

For example - item age, estimated vs tracked time, when item will be done based on flow metrics. And similar concepts.

I am attaching a sketch to show the idea. If it triggers new thoughts, what else should we use it for, share in the comments!