Highlighting or marking the card other than label.

[Preetpal]

Hi could you please explain if Trello cards can be highlighted or marked other than with "labels"?
I want to visually set apart or contrast entries with high relevancy for the current OKR cycle without creating another set of labels for this (since then all the different label "classes" would make it look too crowded).
Maybe there's a configuration setting for this or a "power-up" to install in order to achieve that. 
Thank you in advance

[Daydreamer Mike · Accepted solution]

You can use card covers for this...

https://blog.trello.com/card-covers-and-colors 

[Ost · Accepted solution]

You can also create your own stickers to drag over to covers for added emphasis.