It would be really useful to make Rules based on a task start date, just like the Rules based on a task due date.
I use a kanban-style board to track ongoing projects, and each project has its own task. Two columns I use frequently in my board are “Planned & Upcoming” and “In Progress”. Once the start and due dates for a project are established, it would be helpful if the corresponding task automatically moves from “Planned & Upcoming” to “In Progress” once the start date arrives.