Forlist - A great collaborative to-do list app, worth checking out.

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.

Todo - Todo is a to-do and task list app.

Tyke - Mac menu bar app that @torrez really needed to take notes

Thought Train - Stop using sticky notes to remember what you're doing 📒 🚫

TiddlyWiki - a non-linear personal web notebook