I'm working on a multimedia Android app and I'm not sure which icon to use for unlocking the premium features of the app. These are 1) adding text to images, 2) disabling ads plus 3) disabling the app logo from the final images. More premium features will be added in new versions of the app.
I thought about using the material design open lock icon (!1), but that's very obscure and it also doesn't indicate what the user gets from tapping it. If I use the "add text" icon, the other two premium benefits are not obvious, plus I can't persist the icon across all screens in the app because there's only one that allows users to actually add the text.
Are there any standard Android icons to indicate unlocking premium features? I'd appreciate any thoughts/feedback. Thank you!