This app was mentioned in 5 comments, with an average of 2.40 upvotes
I'm pretty sure it's Neon Pixelz - they've got a pretty massive set of icons and they look great with a hotline miami theme.
Since we are talking about a video game here, and as /u/morallygreypirate said you're gonna want something bright, I'd recommend Neon Pixelz. Great looking set of icons that I think would look kinda cool on that backdrop!