This app was mentioned in 7 comments, with an average of 0.71 upvotes
Since few years Ligna Icons ( https://play.google.com/store/apps/details?id=com.ray.ligna.icons )... I like my icons to be unified and those one are not only looking great but also, when there's no icon designed by the author - properly places a background around original one so every single icon look good enough. It's somewhat future proof that way ;)
linkme: Ligna Icons
Not really flat but square and unified https://play.google.com/store/apps/details?id=com.ray.ligna.icons
There's also https://play.google.com/store/apps/details?id=theme.drumdestroyer.empire.launcher which is "squareish" ;)
The only one that looks alright is https://play.google.com/store/apps/details?id=com.ray.ligna.icons
If that's the case, I used to use Ligna a long time ago. Maybe that's what he means?
https://play.google.com/store/apps/details?id=com.ray.ligna.icons
After few years of experimenting and trying so many icon packs i have actually found best one for me - it's Ligna Icons from Binod Ray. They are neat, consistent and nice to look at. Worth every cent. After that i'm finding every single other pack just... uneven ;)
https://play.google.com/store/apps/details?id=com.ray.ligna.icons