Best apps for knowledge

These are the apps I use daily to keep my brain physically fit.
  1. Blinkist
    All the awesome non fiction books summarized.
  2. Duolingo
    Learn a language while having fun.
  3. Memrise
    A word memory champion created this app. I'm currently learning all of the collective nouns. Because why not.
  4. Podcasts
    These are great to listen to when you have a spare moment and want to learn new things. My current obsession is SEO