Unlock - Monetize your content with a few lines of code

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.

ZELF - Instant money in messengers

Todo.txt - Track your tasks and projects in a plain text file, todo.txt. A todo.

MonetizeJS - Modern payment platform, no server required.

Task Coach - Task Coach is a simple open source todo manager to keep track of personal tasks and todo lists.