There are other tickets asking for a favorites feature for boards, but this will not solve our problem.  Our instance is 2000 users and 300 projects and boards a VERY popular for good reason.  However this success has cone with a downside.  We have so many boards created over time that the list takes a very long time to load.  Users forget to deleted boards they no longer use and being able to manage this by reporting on boards that have not been used in  6-12 months is a basic management need for this.  Viewing if a project has has activity is NOT sufficient for this need as a particular board may no longer be used even if the project is still active.