Gcaf; app that lets you apply icon packs system wide when your launcher doesn't support icon themeing. Works awesome for Aviate (highly recommend Stark with this, looks like they were made for each other) and GEL. Surprised I've never seen this mentioned here. Pretty sure there is a free xda version somewhere too.
This is the Pro Key to Unicon: https://play.google.com/store/apps/details?id=sg.ruqqq.Unicon Buy the developer a meal by buying this key!
This key UNLOCKS:
★ Custom Icon Assignment: Manually map apps to icons from different icon packs!
★ App Drawer Icon Theming: Using stock launcher? No problem! Now you can have pick app drawer icon from icon packs!
★ More to come!