Over at Ensime they have a page dedicated to Emacs Hacks. Although it’s written from the point of view of a Scala developer, the hacks are useful for any Emacs user.
There three sections, one each for
- General hacks
- Scala hacks
- Elisp hacks
there is also a section for Java but it’s not yet completed.
Each of the items either describes a useful package or a bit of Elisp that is too small for a package but which performs some useful task. Unless you’re a complete n00b, you probably already have many of the packages installed but it’s useful to read through the list in case you’re missing something.
The page is a nice resource and well worth taking a look at. If you find just one package that you didn’t already have useful, it will easily pay for the time you spend on it.