Lunyr - A decentralized crowdsourced encyclopedia.
Todo.txt - Track your tasks and projects in a plain text file, todo.txt. A todo.
Tealfeed - A knowledge sharing platform to empower creators
Task Coach - Task Coach is a simple open source todo manager to keep track of personal tasks and todo lists.
Noat Cards - A knowledge learning and sharing platform
Strikethru - Strikethru is a kind of to-do list notebook for managing work lists and staying updated with the important tasks.