I just stepped into the world of smart phones few weeks ago and I am already in love with it. Smart Phones such as Sony Xperia Z2 are quite capable of doing a lot of things, what I personally needed was a way to handle Social Networks, Connect with people and basically do stuff while I am away or not on the system. I just wanted some freedom.
Below are some nifty apps that I use and they're mostly power user tools but they're great for tackling problems. Most of them are highly recommended.
The list is copied from Google Play store btw.
Unsorted list, I will add comments to it later and small reviews. IRC Client, ANDCHAT
Comments
> Calculator++
https://play.google.com/store/apps/details?id=org.solovyev.android.calculator
> Pocketcasts
https://play.google.com/store/apps/details?id=au.com.shiftyjelly.pocketcasts&hl=en
> PowerAmp
https://play.google.com/store/apps/details?id=com.maxmpz.audioplayer&hl=en
> Blackmarket (An "unoffical store")
> f-droid (Open Source app store)
https://f-droid.org/FDroid.apk
> JuiceSSH
https://play.google.com/store/apps/details?id=com.sonelli.juicessh&hl=en
> TurboClient (fast sftp/ftps)
https://play.google.com/store/apps/details?id=turbo.client&hl=en
> Microsoft Apps (Office, OneDrive, OneNote)
https://play.google.com/store/apps/developer?id=Microsoft Corporation&hl=en
> PushBullet (It's hard to explain: https://www.pushbullet.com/)
https://play.google.com/store/apps/details?id=com.pushbullet.android&hl=en