This app was mentioned in 15 comments, with an average of 2.20 upvotes
The icons are Aeon.
And the wallpaper is Limitless Grid (also available on Fdroid). It looks very cool when animated.
I know this is kinda a dead post, but I recently got this icon pack and it fits the transistor theme quite nicely. The other advantage is that it has support for tons of apps.
Wow, you got Neon but not Aeon?
This isn't it, but your picture's icons are very similar to Aeon
For those interested:
Wallpaper Source: Taipei 101 from Romain Trystram homepage / behance.
Launcher - Nova Launcher Prime
Widgets made with Zooper, icon pack is called Aeon (https://play.google.com/store/apps/details?id=stealthychief.theme.aeon), launcher is Nova. Background is this image: http://imgur.com/LswPOXV
Currently using the Aeon Icon Pack and loving how it fits with my background.
I use the Aeon Icon Pack
....And that's not that app I was talking about, here it is https://play.google.com/store/apps/details?id=stealthychief.theme.aeon&hl=en_GB
For those interested:
Wallpaper Source: Taipei 101 from Romain Trystram homepage / behance.
Launcher - Nova Launcher Prime
Aeon - Icon Pack is the one I use and it does a good job imo.
https://play.google.com/store/apps/details?id=stealthychief.theme.aeon
I know I'm late, but I also have a transistor theme and I use the Aeon icon pack.