Formula custom attributesCalculated fields for Trello and Planner with the Placker plugin
Creating and editing custom attributes in PlackerPlacker provides custom text, number, dates, member and traffic light attributes. It is also compatible with Trello custom fields.
Static and dynamic links: Placker custom attribute
Rules to set and clear custom attributesHow to add custom fields to cards based on an automation rule
Member picker custom attributesEnhancing Task Management with Placker's Member Picker Custom Attribute