WoW Retail Talents is the mobile app to check World of Warcraft: Shadowlands talents, PvP talents and covenant abilities for every class!

You can also create and save your own builds

It has a very neat design and is perfectly up-to-date because it is directly using Blizzard API.

All classes and specs.
Talents + PvP Talents + Covenant abilities
Full spell description.

Available in several languages.