There are many but I just want to focus on the word "Innovative", so here I have a few:
[1] Screen Tracker: This app lets you know number of times you checked your Phone a day. It's kind of fun to know amount of time you spend on Phone once the screen is unlocked and it also provides you graphical stats.
[2] Tetra Lockscreen: I like the way it uses SensorCore and provides you graphical stats right on to your lockscreen. Today's addition of Weather widget is cherry on the cake.
[3] Today's Word: It's not just another Dictionary app. I like the way it regularly updates "Today's Word" right on to the lockscreen and notifications work flawlessly well. I could not find an app that flawlessly updates "Word of the Day" on to the lockscreen.
[4] UC Browser: I think this is the first app on WP that uses Picture Password. So, innovative enough