Plex mobile player would work great on this platform. So Plex please take note and make a Plex app for this Mobile OS! Who else thinks this is a great idea? Many would pay for this.
Many people would like to see a media player on Ubuntu Phones and Tablets. This year many new Ubuntu mobile devices are coming out. http://www.omgubuntu.co.uk/2016/02/android-oems-will-ship-ubuntu-phones-year-say-canonical
About Ubuntu Phones-
http://www.ubuntu.com/phone
http://www.omgubuntu.co.uk/category/ubuntu-phone-os
Video
About Ubuntu Tablets-
http://www.ubuntu.com/tablet
http://www.omgubuntu.co.uk/category/ubuntu-tablet-2
Video
SDK for developers (Phone and Tablet)
http://www.ubuntu.com/phone/developers
http://www.ubuntu.com/tablet/developers