Sourceforge is the main repository for Erlang projects, with lots of examples and interesting applications being developed.

The Dialyzer is a static analysis tool that identifies software discrepancies such as type errors, unreachable code, redundant tests, virtual machine bytecode which is unsafe in single Erlang modules or entire applications.

Erlang/QuickCheck is a library for random testing of Erlang programs against specifications.

User-contributed software at the open source Erlang site.

Provides features similar to IntelliSense or CodeSense in other editors. It can be enabled in an Erlang buffer or in the Erlang Shell buffer.