OneNote - Get the OneNote app for free on your tablet, phone, and computer, so you can capture your ideas and to-do lists in one place wherever you are. Or try OneNote with Office for free.

ManualsLib - Just enter the keywords in the search field and find what you are looking for!

Evernote - Bring your life's work together in one digital workspace. Evernote is the place to collect inspirational ideas, write meaningful words, and move your important projects forward.

Manuzoid - Repository that includes user manuals for various products

Laverna - Laverna is a JavaScript note taking application with Markdown editor and encryption support.

ManualAgent - Manuals and guides