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.
DEVONthink - DEVONtechnologies develops DEVONthink, DEVONagent, and other Mac and iOS apps for document and information management and web research.
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.
TaskSurfer - TaskSurfer gives you all of the tools you need to manage things the way you want.
All Note - All Note app contains features to enable users to share their world-changing ideas with their friends and family members after writing them on the mobile phone’s screen. It supports various file formats such as HTML, Docx, doc, and pdf, etc.
HoudahSpot - Advanced File Search Utility for Mac OS X