Onyx is a free system maintenance tool for Mac OS X.
One of the nice things about Onyx is that it covers everything you can think of. It’s packed with tools that you might want to use often, plus some you might use only once in a blue moon. But they’re all there, in one place.
MarsEdit is the best blogging tool for OS X, bar none. If you do blogging for money or just for the love of it, MarsEdit is a dream come true for you. It will save you lots of hassle and hours of time.
If you’ve ever used and loved the “Archive” function in Gmail or MobileMe, then found yourself missing it while using Apple’s own Mail application, this simple free plugin is a dream come true.
It’s an Archive button for Mail, and you can guess what it does. Instead of having to mess around with filing messages into folders, a single click will throw them into the archive. It even comes with its own ready-made keyboard shortcut (Command+Option+S), to make archiving even faster and easier.
When you need to find something specific, use Mail’s own search, which is quite up to the task of hunting through enormous archives (I’ve used Mail in this way, as a backup for my Gmail account, for years now).
Applejack is a command-line application for rescuing your computer when disaster strikes, or threatens to strike.
Don’t let the “command-line” bit frighten you off. Applejack is probably the easiest-to-use command-line application I’ve ever seen. It was built for ordinary people to use, and won’t bamboozle you with geekspeak.