Just a short note ...
I've been using this app at the Table on Gamenights and it has been a HUGE help when looking up Spells and Class features.
Complete Reference for DnD 5E
(It's also listed in the sidebar to the right ...)
After downloading it, inside the app is a feature that takes you to the Apps Support Site to download addition WotC content ... I highly recommend this. There's more than a couple DLs, but it really takes very little time to do. Then, just click on the downloaded content in your phones/tablets download folder and it automatically updates the App.