Top Rated for Android Studio

Non Project Files Unlocker

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

ToolWindow Manager

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

Frame Switcher

Plugin for more convenient switching between projects/frames/windows than is alt-tab or Window menu.

SequenceDiagram

By vanco
SequenceDiagram for IntelliJ IDEA http://vanco.github.io/SequencePlugin. with this plugin, you can + generate Simple Sequence Diagram.

XPathView + XSLT-Support

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

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".

Embedded Linux JVM Debugger (Raspberry Pi, BeagleBone Black, Intel Galileo II, and several other IoT Devices)

Java Runner/Debugger for Embedded Systems/IoT Devices that run on any variant of the Embedded Linux Kernel.

Emoji Support Plugin

Intellij plugin for supporting auto-complete for Emoji.