Task Coach - Task Coach is a simple open source todo manager to keep track of personal tasks and todo lists.
Zen Planner - Zen Planner's fitness membership management software helps you grow your box, gym or studio with scheduling, automated billing & more. Try it now for free!
EssentialPIM - EssentialPIM is a free Personal Information Manager that keeps up with the times and lets you manage appointments, tasks, notes, contacts, password entries and email messages across multiple devices and cloud applications.
Glofox - Powerful Gym and Studio Management Software.
Todo.txt - Track your tasks and projects in a plain text file, todo.txt. A todo.
Pike13 - Pike13 provides a mobile-first solution for "on-the-go" owners of small service business who are trapped in a paper world trying to manage their clients.