Rebel Notes - Rebel aims to provide you a distraction-free note taking experience. Focus more on writing and less on formatting and saving. As you write your note, Rebel will format it based on your markdown syntax.
Flashnote - Flashnote is a quick notes manager
Google Keep - Capture notes, share them with others, and access them from your computer, phone or tablet. Free with a Google account.
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.
Notepin - Extremely simple note-taking + blogging ✍️
Task Coach - Task Coach is a simple open source todo manager to keep track of personal tasks and todo lists.