This app was mentioned in 15 comments, with an average of 19.27 upvotes
If they're gonna do it they should add it at a system level, like Unicon does. Sadly I'm too happy with stock Nexusville to bother with Xposed anymore, but this is the only way I've ever been able to digest icon themes. The mismatch with Recent Apps when it's implemented only in the launcher just makes for a gross UX.
Haven't found anything useful before, if you apply a theme that has different icons that will change and fix the system icons, but 3rd party apps will still by broken AFAIK.
I haven't tried it, but I think maybe if you have Xposed and install Unicon and apply an icon pack system-wide that'd fix it, but I've never tried that since I don't have Xposed installed.
There is an option using a root & xposed app that changes the icons at the system level, which in turn would change the icons on the apps edge. AFAIK that's the best option. https://play.google.com/store/apps/details?id=sg.ruqqq.Unicon
you can with xposed modules, Unicon is the most popular solution for changing icons system wide. another xposed option is flipster that allows you to use any image for an icon, where unicon is limited to icon packs.
Maybe check out Unicon? It seems to do what you suggested. The icon looks different to me, so perhaps this is just an updated version of what I used to use.
https://play.google.com/store/apps/details?id=sg.ruqqq.Unicon
That said, I would suggest trying Action Launcher 3. It can look stock, but has so many additional features (and would make this app suggestion meaningless)
I don't think GEL applies the Marshmallow icons. From my experience with it, it just uses the device's default.
And if you're interested in rooting and tinkering, there's this Xposed module called Unicon that will allow you to change your icons system-wide. So for example if you downloaded a material style icon pack such as Candycons, the icons would be applied everywhere. Launcher, recents, settings pages, etc.
Interesting. One of these days I'll disable the module and see if there are any changes at all. Although I basically can't live without it, it makes Trebuchet so much better than it already is.
Also, here's the link.
there used to be Unicon module for Xposed, but the Play Store description says it's discontinued.
You can use Unicon. It requires Xposed and changes your icons in the whole system. https://play.google.com/store/apps/details?id=sg.ruqqq.Unicon
Edit: Join the beta here
This app worked well for me. You need root though.
Using the Google Now launcher with Unicon Beta Xposed module to change the icons.
Muzei with the Pics from Reddit plugin changing every hour.
The battery and weather I made myself in Zooper.
Also using InversionUI layers theme