Gists are nice, but I prefer self-hosting since it allows me to tell a story alongside the code.

Agnostic:

• More humane time intervals

By language/platform:

• Git
• Jekyll
• Objective-C
• Swift
• Web

Git

• Git diff support for plists
• Git diff support for SQLite databases
• Better diff hunk headers with Swift¹

Jekyll

• A plugin providing support for Graphviz
• A page hosting various code highlighting themes²

Objective-C

• defer for Objective-C

Swift

• .onLazyHover, for when .onHover is too eager

Web

• Some CSS and JS for decorating external links on a page.
• Automatic copy buttons for all elements with class="copyable".