GageList - Simple online calibration software
Todoist - Todoist is a to-do list that helps you get organized, at work and in life.
QMSys Calibration Management - Calibration Management
Todo.txt - Track your tasks and projects in a plain text file, todo.txt. A todo.
A2Z MANAGER - Calibration Management and Calibration
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.