Well, you have the Authenticator-app which you really you use right now if you dont already have one. Then you have the Armory-app, which could be fun and usefull to browse different partymembers and confirming the proffesions and such.
And then you have the Gearscore-app.... Well, yeah...
Only go after "Official" apps if you know what I mean - don´t go and download any guides and such, because they could be abit fishy. But I´m not sure about those...