Not sure if this is the right spot but had a suggestion for Unity. A TODO: option. For example in the Hierarchy under the scene view where you have all objects, camera etc. Maybe have a button that illuminates or something if you select the object and select TODO reminder. Also in the Project view for example if you select a script or animation file or anything else maybe an option for TODO: reminder and a illuminated icon appears in front or after the file/object remining you you wanted to do something else in the file/object or whatever. When your done you could just unmark for TODO reminder same way. For example if you have a folder called Animation. If you have an animation file in that folder that you selected to add a TODO reminder in front of the main folder under project view a small illuminated icon will appear to remind you you have a todo under that folder tree.