Add a thick stroke to the outside edge of a row, in a different colour from the row itself.
This can be used to highlight a selected row, or show that a row has been tagged or is different in some way from the rest of the rows.
This is also helpful for adding brand colours to a table, if you've got a reason to be highlighting rows like this in the first place.
This technique is more subtle than colouring the whole row to show something is different about it.
If the stroke is too thin it might be hard to notice for the user. Same if the colour is not noticeable enough.