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.
24me - Next Generation Personal Assistant
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.
WeekCalendar - WeekCalendar is an all-in-one calendar application designed to provide everyone with all the features they need to work to their fullest.
Joplin - Joplin is a free, open source note taking and to-do application, which can handle a large number of notes organised into notebooks. The notes are searchable, tagged and modified either from the applications directly or from your own text editor.
Calvetica - The fast calendar for iPhone. Add an event in just two quick taps.