Top Rated for IntelliJ IDEA Community Edition

Grammar-Kit

BNF Grammars and JFlex lexers editor.

ToolWindow Manager

Allows availability of IDEA ToolWindow buttons to be controlled on a per-project basis.

Non Project Files Unlocker

Disables annoying dialog for unlocking non-project files - IDEA-125379.

hybris integration

This plugin is a plugin for SAP Hybris Commerce integration.

Lombok Plugin

IntelliJ Lombok plugin.

Presentation Assistant

This plugin shows name and Win/Mac shortcuts of any action you invoke (View | Descriptions of Actions).

XPathView + XSLT-Support

The XPath part of the plugin provides a possibility to evaluate XPath expressions against any XML document opened in IDEA.

WicketForge

WicketForge assists developers creating Wicket applications.

Jelastic Cloud Platform Integration

Rate plugin | Free trial | Docs.

Tab Shifter

This is a plugin with a bunch of actions to move tabs between editor splits and resize splits. Actions are added to "Main Menu -> Window -> Tab Shifter".