Some of the websites/apps to enhance productivity and skillsets

These are the apps that I use that make me feel more productive and help me to think better

• Daily facts app,Daily Facts - Android Apps on Google Play, I use this to learn something new everyday.
• Reddit,Reddit: The Official App - Android Apps on Google Play, this is quite awesome to get to know all the new things that are happening and what people are saying about it without needing to wattch 30–40 minute news that can break your heart.
• Cell world,Cell World - Android Apps on Google Play, I learned a lot about cells using the app.
• Physical theories,Physical theories - Android Apps on Google Play, helped me a lot in physics.
• Speed anatomy,Speed Anatomy Quiz Free - Android Apps on Google Play, now I know what every single part of the body is called.
• Math academy,Math Academy: Zero in to Win! - Android Apps on Google Play, this apps so easy and fun, all you have to do is to make it equal to 0, it’s not as easy as it sounds.
• BBC news,BBC News - Android Apps on Google Play, where you can know all the political things.
• Calculus quick notes,Calculus Quick Notes - Android Apps on Google Play, helps a lot if you’re in high school.
• Historical calendar,Today in History Calendar - Android Apps on Google Play, you know what happened in this particual day for the past thousands of years, events, which famous person died, who was born etc.
• TED,TED - Android Apps on Google Play, quiet obvious.
• Vocabulary builder, Vocabulary Builder - Android Apps on Google Play, helped me a lot in learning new words and idioms and such
• Malmath,MalMath: Step by step solver - Android Apps on Google Play, no only it solves an euquation but also shows you the steps.
• Elevate,Elevate - Brain Training - Android Apps on Google Play, this app has quite a lot in it.

Here are few sites

• Codec academy, Learn, you can learn coding easily
• Khan academy, Khan Academy, you learn everything here
• Coursera - Free Online Courses From Top Universities | Coursera, not only you can learn but you can also get a certificate

Hope this helped!