Many/most journals release special issues dedicated to specific topics. It would be valuable to be able to mark a whole issue as a favourite, so that I can easily return again and again until I've read or saved all articles of interest (particularly useful for those weekly journals, where it is easy to get behind). I was thinking that enabling a change of colour in the list of issues would be one way of handling this, or enabling the addition of an icon to the list of available issues, but there are probably other/better ideas.