Trello, Todoist, OpenProject, Workflowy, ClickUp, TickTick, Habitica, Org mode, Zenkit, Quire, GTD-Free, Tasks.org, Remember The Milk, Zanshin, Task Hammer, Simple Outliner, GTDNext, Calendar Notifications Plus, The Big Picture, Todoist-Linux, topydo, What-Do?, Yalla, TimeIO, Todoed, mGSD, TodoToday, Alinof ToDoList, LiquidTime, Hightrack are some alternatives to Hero Panel.