Task List Enhancements

I would be wonderful if task lists could have some context menu options or commands such as the following:
• Check / uncheck all items
• Delete checked items
• Hide checked items (in a collapsible section below the list, such as how Google Keep does it)

That last suggestion could perhaps even be a global setting on by default as it's pretty common in other systems, but I personally like the idea of having the choice per-list.