I\'m gonna release my app, it\'s a 1.2Mb apk that includes about 120 icons in 4 different formats (ldpi, mdpi, hdpi, x-hdpi).
If I add xx-dpi and xxx-hdpi icons the
I think you should focus on the most popular screen densities, which are hdpi, xhdpi, and xxhdpi. See this link for the current worldwide average distribution of each density.
We had to add xxxhdpi to our app for the Nexus 6, LG G3, and Samsung Galaxy Note 4. There will be more xxxdhpi devices in the future.