Top Rated for IntelliJ IDEA Community Edition

GoToTabs

The plugin adds menu actions allowing you to go to a specific tab.

Lines Sorter

Add Sort Lines action in Edit menu to sort selected lines or whole file if selection is empty.

InnerBuilder

Adds a Builder action to the Generate menu (Alt+Insert) which generates an inner builder class as described in Effective Java.

Maven Helper

A must have plugin for working with Maven.

PlantUML integration

PlantUML diagramming tool integration.

EmmyLua

Support for Lua programming language.

CloudSlang Plugin

IntelliJ CloudSlang plugin.

Save Actions

Supports configurable, Eclipse like, save actions, including "organize imports", "reformat code", "rearrange code", "compile file" and some quick fixes for Java like...

Multirun

Allows to run multiple run configurations at once: group multiple run configurations and start them in a single click.

Custom Postfix Templates

Documentation | Screencast | Predefined templates.