Every icon with many elements is bad, it's too hard to recognize in the case where it small. The icon must be simple and recognizable. And if app name is far from original, then icon must point user what about this app

Some Behance posts I found by simple search:

Ubuntu Touch GUI elements by Taras Savytskyi
https://www.behance.net/gallery/27591427/Ubuntu-Touch-GUI-Free

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Roman Nguyen concept on Behance
https://www.behance.net/gallery/28804097/Ubuntu-1604-Stupendously-Hot-Charmander-concept

Pablo Marlasca concept on Behance
https://www.behance.net/gallery/29848255/Ubuntu-Touch-Vibrant-Venice

Alex Milazzo on Ubuntu System and Contextual Menus
https://www.behance.net/gallery/9167887/Ubuntu-System-and-Contextual-Menus

Convergence mockups by Alex Milazzo
https://www.behance.net/gallery/51028087/Ubuntu-Mobile-Tablet-and-desktop-convergence

App concept by Jacek Kruk
https://www.behance.net/gallery/18228723/Skydiv-skydiving-logbook

Clock App for Ubuntu Touch by Lucas Romero
https://www.behance.net/gallery/14468723/Clock-App-for-Ubuntu-Touch