There are always the first extensions I install on a new Mac, or if I do a clean install on one of my older machines. As of writing this, they both still work without any issues.
Removes all sorts of un-necessary junk for the URL so that you can easily copy the URL for sharing. Removes things like: utm_source=, etc.
Minimal Status Bar:
"This is an extension to provide a minimal (Google Chrome-like) status bar for Safari. It also has built-in longurl support to convert those pesky and opaque short urls to long ones again."