I would like the ability to have milestones or project stages. Many of my projects have 40 or more tasks and having them in a kanban board just organized by statuses under Not started can be confusing. I would like to see an additional kanban board that allows us to create milestones and then organize our tasks within them. For example I am a website designer so my milestones include Onboarding, Discovery, Site Architecture, UX Design, etc...
Milestones could also have the option once all tasks are finished within them to be approved and signed by the client. For some projects after a certian milestone is completed and approved an invoice may get sent out.