7zipper

Price: free

Allows for easy handling of 7z archives.



Play Store Link Allows for easy handling of 7z archives.

A Better Camera

Price: free, $4 for pro version

Advanced camera controls and other cool features like customizable HDR.



Play Store Link



Pro Version Advanced camera controls and other cool features like customizable HDR.

AirDroid

Price: free, prices vary for Premium version

Allows remote control of an Android device from a "real" computer (to a degree).



Play Store Link Allows remote control of an Android device from a "real" computer (to a degree).

Alarm Clock Xtreme

Price: free, $1.99 for ad-free version

The most granular alarm settings I've ever seen.



Play Store Link



Ad-Free Version The most granular alarm settings I've ever seen.

Android Pay

Price: free

While it has other stuff, its core functionality is NFC payments.

It does this well, and works anywhere that Apple Pay is supported.



Play Store Link While it has other stuff, its core functionality is NFC payments.It does this well, and works anywhere that Apple Pay is supported.

ASTRO File Manager

Price: free, $3.99 for ad-free version

Copy and move files, deal with cloud storage, and more with ease.



Play Store Link



Ad-Free Version Copy and move files, deal with cloud storage, and more with ease.

Automatic Call Recorder

Price: free

DISCLAIMER: not all states are one-party states. Check your local laws.

The only app of its kind I've found to work with the Note 4.



Play Store Link The only app of its kind I've found to work with the Note 4.

Battery Log

Price: free

Shows detailed text or graph logs of battery level and temperature.



Play Store Link Shows detailed text or graph logs of battery level and temperature.

Boats for Voat

Price: free

Currently the most useful mobile client for Voat,

a censorship-free reddit alternative.



Play Store Link Currently the most useful mobile client for Voat,a censorship-free reddit alternative.

CamScanner

Price: free

You just might not need a scanner anymore. It's that good.



Play Store Link You just might not need a scanner anymore. It's that good.

Commandr

Price: free

Supercharges Google Now with lots of extra goodies added to voice control.



Play Store Link Supercharges Google Now with lots of extra goodies added to voice control.

DiskUsage

Price: free

The Android equivalent of WinDirStat - shows disk usage visually.



Play Store Link The Android equivalent of WinDirStat - shows disk usage visually.

Firefox

Price: free

Offers some functionality that Chrome doesn't,

and often works when Chrome displays weirdly.



Play Store Link Beta Version Offers some functionality that Chrome doesn't,and often works when Chrome displays weirdly.

Goggles

Price: free

Reads barcodes such as QR and UPC, and can OCR certain info for you.



Play Store Link Reads barcodes such as QR and UPC, and can OCR certain info for you.

Keep

Price: free

Simple, functional note-taking with reminders



Play Store Link Simple, functional note-taking with reminders

Kinemaster

Price: free

The closest thing to iMovie for Android.



Play Store Link The closest thing to iMovie for Android.

Keepass2Android

Price: free

KeePass-compatible password manager



Play Store Link KeePass-compatible password manager

MX Player

Price: free, $5.99 for ad-free version

The VLC of Android, before VLC was on Android.

Everything you might want in a media player.



Play Store Link



Ad-Free Version The VLC of Android, before VLC was on Android.Everything you might want in a media player.

Omni Swipe

Price: free

An unobtrusive HUD that's only there when you need it

and includes handy shortcuts like a flashlight.



Play Store Link An unobtrusive HUD that's only there when you need itand includes handy shortcuts like a flashlight.

Pushbullet

Price: free

Notification mirroring and cross-device sharing made easy.

One of those apps you'll use constantly without realizing it's even there.



Play Store Link Notification mirroring and cross-device sharing made easy.One of those apps you'll use constantly without realizing it's even there.

reddit is fun

Price: free, $1.99 for golden platinum edition

Currently the most useful mobile client for reddit,

an online news aggregator with social commentary.



Consider using

or reddit may actively censor unpopular opinions.Consider using Voat instead of or in addition to reddit,or Boats for Voat on mobile.



Play Store Link Currently the most useful mobile client for reddit,an online news aggregator with social commentary.

RedPhone

Price: free

End-to-end encrypted voice communications - works great with TextSecure.

Works over a data connection.



Play Store Link End-to-end encrypted voice communications - works great with TextSecure.Works over a data connection.

Ruler App

Price: free

Another self-explanatory one; tell it your screen size and it's ready to go.



Play Store Link Another self-explanatory one; tell it your screen size and it's ready to go.

Safest Text Auto Reply

Price: free

Reliable auto-responder for texts and phone calls. Useful when driving.



Play Store Link Reliable auto-responder for texts and phone calls. Useful when driving.

SoundHound

Price: free, $5.99 for ∞ version

What's that song? Let your phone listen and it'll tell you in a heartbeat.



Play Store Link ∞ version What's that song? Let your phone listen and it'll tell you in a heartbeat.

Speedtest

Price: free

One-step connection speed test. Be careful if you're on a capped data plan.



Play Store Link One-step connection speed test. Be careful if you're on a capped data plan.

Tasker

Price: $2.99

Play Store description nails it: "Total Automation, From Settings to SMS."

tl;dr Makes anything trigger anything.



Play Store Link Play Store description nails it: "Total Automation, From Settings to SMS."tl;dr Makes anything trigger anything.

TeamViewer

Price: free

Control your computers from your phone wherever there's internet.



Play Store Link Control your computers from your phone wherever there's internet.

Textra

Price: free

SMS heaven. Popup messages that disappear when replied to is the main draw.

Works great with Pushbullet and Android Wear.



Play Store Link SMS heaven. Popup messages that disappear when replied to is the main draw.Works great with Pushbullet and Android Wear.

TextSecure

Price: free

End-to-end encrypted text communications - works great with RedPhone.

Works over a data connection.



Play Store Link End-to-end encrypted text communications - works great with RedPhone.Works over a data connection.