There are lots of great tools out there. Far too many to try. Here are the ones that I’ve tried, and found worth recommending. Mostly they’re OS X Developer Things Quiver is a “Programmer’s Notebook”. I’ve recently switched to it from CodeBox which seems to have been abandoned by its developer. I’ve got some minor quibbles with Quiver, but overall it’s pretty nice and I’ll be bringing all my code snippets and reference material over to it.